I have rewritten the first part of the timeline (up to April 1863), to include a history of the American Civil War as it played out in this timeline.
December 1860--South Carolina secedes from the Union.
January 1861--Alabama, Mississippi, Georgia, Florida, and Louisiana secede from the Union.
February 1861--Texas secedes from the Union. Representatives of the seceded States meet in Montgomery, Alabama, to discuss the formation of a new government. On February 8, a Constitution is adopted and the Confederate States of America is officially declared in existence. Jefferson Davis is sworn in as President of the Confederacy on February 18, with Alexander H. Stephens as his Vice President.
March 1861--On March 4, Abraham Lincoln is sworn in as President of the United States at Washington, D.C. In his inauguration address, he declares secession illegal, and vows to uphold the Union. He does, however, attempt to conciliate the South by denying he has any plans to interfere with slavery where it already exists.
April 1861--A crisis over the status of Fort Sumter, in Charleston Harbor, turns violent when Confederate forces open fire on the fort in order to force its surrender before the garrison can be augmented and resupplied by a Federal fleet sent by President Lincoln for that purpose. With these shots, the American Civil War begins. Three days later, President Lincoln issues a call or 75,000 volunteers and asks the States to supply their militias for the purpose of suppressing the “insurrection,” as he calls it. On that same day (April 15), Caleb Huse, Confederate Purchasing Agent, sets sail for England. In reaction to President Lincoln’s request for it’s State Militia, Virginia secedes from the Union on April 17. On April 19, President Lincoln declares a blockade of Confederate ports. This is a blunder, as by declaring a blockade, Lincoln has tacitly granted the Confederacy “belligerent” status under international law. Now foreign nations may legally sell arms and equipment to the Confederacy.
April 1861 onward--The Confederacy initially has little difficulty equipping it’s armies. A supply of almost 300,000 military firearms (a majority of which are obsolete, but still serviceable, smoothbore muskets) had been amassed by the various State governments, most of which become available to the Confederate army at the outbreak of war. The Confederates are able to equip their main field armies for campaigning in 1861 and early 1862 with these weapons. However, the Confederacy has little capacity to produce more, and if the war lasts more than a few months, that lack will soon make itself felt on the battlefield. It is vital that reliable supplies of foreign imported arms be established.
May 1861--North Carolina and Arkansas secede from the Union. Britain declares it’s neutrality in the conflict, but states that it will accord both sides their full rights as belligerents. Caleb Huse takes full advantage of this by signing major arms contracts with all the major British arms makers. The Confederate Congress votes to relocate the Confederate capital from Montgomery, Alabama to Richmond, Virginia.
June 1861--Tennessee secedes from the Union. Emperor Napoleon III of France openly declares his support of the Union, saying that France will not support a “rebellion against their lawful government by a cadre of detestable slavers.” He orders Confederate envoys and purchasing agents expelled from France. French diplomats communicate Napoleon’s concern over Britain’s neutral stance vis-à-vis the Confederacy.
July 1861--Following intense diplomatic negotiations between France and Britain, including a personal letter from Napoleon III to Queen Victoria, the British government reverses it’s diplomatic stance toward the Confederacy. Confederate diplomats and purchasing agents are expelled from Britain, and the British government forces all British arms makers to abrogate the contracts which have recently been made with Caleb Huse. The Confederacy will have no access to British arsenals during the war. The Battle of First Manassas proceeds as per OTL. The Confederates win a major victory, but are unable to follow it up by pursuing the beaten Union army.
July 1861-Spring 1862--Events of the American Civil War proceed as per OTL, with one major exception…Confederate arms purchasers, having been kicked out of Britain and France, find their sources of supply limited to Belgian firms (who will sell to anybody, for a price), as well as Austria and Prussia. Belgium provides approximately 50,000 copies of the highly regarded British Enfield rifle musket, while Austria sells about 100,000 modern Lorenz rifle muskets, while Prussia empties it’s warehouses of surplus antiquated flintlocks, most of which saw hard service during the Napoleonic Wars over 40 years before. Most of what is bought from Prussia proves to be completely unserviceable and is a complete waste of money, but the Belgian and Austrian rifles are a welcome addition to Confederate stockpiles. However, it is not enough, and by the Spring of 1862, Confederate armies…especially in the Western Theater, are feeling the pinch.
October 1861--Treaty of London. Britain, France and Spain decide to unite their efforts to collect unpaid debts from the Mexican government.
December 1861--Spanish fleet and army arrives at Vera Cruz.
1862--In Prussia, the largest of the German states, a member of the landed aristocracy, Otto von Bismarck, becomes Chancellor. Representing the king, he declares that his government is to rule without parliament.
January 1862--British and French fleets arrive at Vera Cruz.
February 1862--Forts Henry and Donelson fall to Union forces commanded by Major General Ulysses S. Grant. With the fall of these forts, central Tennessee becomes undefendable, and Confederate forces withdraw southward to Corinth, Mississippi. The Union Army occupies Nashville on February 25.
March 1862--French army lands in Mexico. President Lincoln removed George B. McClellan from his position as General-in-Chief of Union forces and places him in command of the Army of the Potomac, tasked with the capture of Richmond. Clash between the C.S.S. Virginia…a Confederate ironclad constructed on the burned hulk of the former U.S.S. Merrimac…and the U.S.S. Monitor, a new turreted ironclad designed by John Ericsson. The battle is tactically a draw, but strategically a Union victory. The Virginia had destroyed two wooden U.S. warships the previous day, but the Monitor is able to prevent the Confederate ironclad from destroying the rest of the Union blockade fleet in Hampton Roads. The Virginia returns to port, and the two ironclads will never meet again in battle.
April 1862--A convention of the London Treaty powers decides to withdraw from Mexico. Napoleon III, however, does not immediately go along with the other powers, and French troops remain.
In Virginia, Major General George B. McClellan’s Army of the Potomac, having been transported by sea to Fort Monroe, advances west along the Peninsula toward Richmond. On April 5, McClellan lays siege to Confederate forces at Yorktown, Virginia.
At Corinth, Mississippi, General Albert Sidney Johnston had hoped to gather enough troops to make possible an attack on the army of Major General Ulysses S. Grant, which was then encamped at Pittsburg Landing, Tennessee. However, the failure of Confederate agents to secure any English or French arms, and the top priority given to arming the troops defending the Confederate capital in Virginia, means that he has not had the same success which he enjoyed in OTL. As a result, he abandons his planned assault on Grant’s army. On April 6, 1862, Grant is joined by the army of Major General Don Carlos Buell, and together, the combined Union host of over 80,000 advances on Corinth on April 10. Outnumbered almost three-to-one, General Johnston orders the Confederate evacuation of Corinth on April 11. Johnston’s army retreats to Jackson, Mississippi. Meanwhile, on April 8, Island Number 10 surrenders to Union forces under John Pope, opening the Mississippi River to Union forces all the way down to Fort Pillow, Tennessee. And on April 24, Union warships under David G. Farragut run past Forts Jackson and St. Philip on the Mississippi River, the only defenses of New Orleans. New Orleans itself falls on April 25.
May 1862--On May 4, Confederate forces slip away from Yorktown toward Williamsburg, Virginia. General McClellan’s Army of the Potomac follows…slowly. McClellan is operating on delusions that he is vastly outnumbered by Confederate forces, due largely to specious intelligence reports provided by Allan Pinkerton, and is very cautious in his pursuit of the retreating enemy. On May 5, 1862, the Battle of Puebla is fought between Mexican and French forces. French troops suffer a humiliating defeat at the hand of the Mexican forces, although casualties are relatively light. On May 10, the combined Union armies of Ulysses S. Grant and Don Carlos Buell move south from Corinth, Mississippi, toward the Mississippi State capital at Jackson, which is defended by General Albert Sidney Johnston’s Army of Mississippi. Johnston has been reinforced somewhat by refugee troops from New Orleans and from elsewhere, but is still is outnumbered by over two to one. Jackson is the major rail nexus connecting the port of Vicksburg, Mississippi…a vital link between it’s States east and west of the Mississippi River…with the rest of the Confederacy. It must be held. Accordingly, Johnston orders the construction of strong fortifications around the city. His works are repeatedly assaulted by the Union armies over May 27-29, 1862. Although the Confederates fight valiantly, the odds are too great. A Union assault on May 29 pierces the Confederate lines, and Johnston’s army is shattered. Both Johnston and his second in command, General P.G. T. Beauregard, are killed as they brave enemy fire trying to retrieve the situation. Survivors of the Confederate forces retreat toward Vicksburg, where they augment the garrison there, or toward Montgomery, Alabama, where a Confederate relief force is being slowly concentrated. On May 31, Confederate forces under General Joseph E. Johnston launch an assault against an isolated wing of McClellan’s Union Army of the Potomac at the Battle of Seven Pines (Fair Oaks). General Johnston is severely wounded and forced to relinquish his command.
June 1862--On June 1, Robert E. Lee is placed in command of the Confederate Army of the Potomac, defending Richmond, which he renames the Army of Northern Virginia. However, on that same day, President Jefferson Davis, faced with the collapsing situation in the West, orders the withdrawal of troops from Virginia and sends them west. Among these is The Army of the Valley, commanded by Major General Thomas Jonathan Jackson, which has, up to now, been bedeviling Union forces in the Shenandoah Valley. Troops from the main Confederate army protecting Richmond are also diverted west, and even Allan Pinkerton cannot fail to notice that there are not as many Confederates around as previously. He reports this to General McClellan, who is emboldened to speed up his advance on Richmond. General Robert E. Lee, who had been planning to again attack the Union Army, finds that with his depleted forces, he is unable to do so. McClellan reaches the Confederate fortifications outside Richmond and begins siege operations on June 15. A frustrated Robert E. Lee can do nothing but watch as his army is encircled by vastly superior Union forces. Meanwhile, on June 6, the Battle of Memphis is fought between Union and Confederate fleets. The Union forces are victorious. Memphis falls to Union troops shortly thereafter. Vicksburg is now the Confederacy’s only remaining link between it’s cis-Mississippi and trans-Mississippi States. Meanwhile in France, upon learning of the disaster at Puebla, Napoleon III decides that Mexico might not be worth the effort it would take to seize it, and orders the withdrawal of French troops.
June 25-August 2, 1862--The Siege of Richmond. McClellan brings up heavy artillery to bombard the Confederate works and the city itself. Several Union assaults are beaten back with heavy losses during June and July, but finally, on August 2, a major Union assault breaks through into the city. President Jefferson Davis, who had stubbornly refused advice from General Lee to evacuate the city, is caught and killed by rampaging Union cavalry commanded by Brigadier General George Armstrong Custer as he attempts to flee the Confederate White House. Vice President Alexander H. Stephens, however, escapes the city, along with most of the rest of the Confederate government. Union forces burn much of the city to the ground. Also killed is another Union cavalry commander, John Buford.
June 1862 onward--Recriminations in France over the defeat at Puebla lead to an earlier reform of the French military. Minister of War Jacques Louis Randon, with the approval of Emperor Napoleon III, closes loopholes in the national conscription regulations, and increases bonuses for reenlistment of veteran troops, both of which greatly increase the strength and quality of the French military.
July 1862--Union Generals Grant and Buell follow up their victory at Jackson with an advance on Vicksburg, to which they lay siege on July 12. In this they are supported by the Union fleet, coming down from Memphis and up from New Orleans, as well as by another Union Army moving north from New Orleans under Major General Benjamin Butler. Butler’s force is stymied by the garrison of Port Hudson, Louisiana, however, and stops to lay siege to that place. Grant and Buell lay siege to Vicksburg. Meanwhile, Major General Thomas Jonathan Jackson, the senior officer available in Montgomery upon his arrival there, takes command of the new Confederate Army of Alabama, which is being formed at that place. Jackson finds himself in command of over 40,000 troops, but nevertheless knows he is still greatly outnumbered by the Union forces in Mississippi. He decides to embark on a bold strategy…strike north, into Tennessee, and threaten Nashville, in the hope that most, if not all, of the Union forces now rampaging through Mississippi will be recalled north to defend their supply lines through Tennessee. Jackson marches north from Montgomery on July 9, 1862. By the end of the month he is into Tennessee, and there renames his army as the Army of Tennessee.
August 1862--Upon learning of Jackson’s move northward on August 1, Major General Don Carlos Buell, with his army, is detached from the force besieging Vicksburg and transported by river to Memphis, where they march to intercept Jackson’s Army of Alabama. As described elsewhere, Richmond falls on August 2, 1862. Confederate General Robert E. Lee manages to extricate most of his army and fall back, along with the Confederate government, to Danville, Virginia, where they can get railroad connections south…the new President, Alexander H. Stephens, has decided to move the Confederate capital back to Montgomery. Union commander McClellan does not vigorously pursue, and the Confederate troops are able to get away by rail. Governor John Letcher vehemently protests this withdrawal, but to no avail. He sets up a State government-in-exile in North Carolina, but his governorship is effectively over. Virginia, abandoned by the Confederate armies, is basically out of the war at this point, and comes under Union occupation. On August 20, the forces of Buell and Jackson meet near Franklin, Tennessee. Jackson inflicts a severe defeat on the Union army, which is forced to retreat back toward Memphis. Jackson pursues, and catches Buell again on August 25. In fighting near the old Union encampment at Pittsburg Landing, Tennessee, the Union defeat turns into a rout. Don Carlos Buell is killed, along with several other officers, including one of his Division commanders, Brigadier General George Henry Thomas.
September 1862--By September 1, Confederate government re-establishes itself in Montgomery. President Alexander H. Stephens, however, is a realist, and he feels that Confederate victory is no longer possible. Nevertheless, he believes that Jackson’s victories in Tennessee have given him some possible bargaining power, and he sends envoys to President Lincoln, asking for peace terms. This is the beginning of what will prove to be seven months of on-again, off-again negotiation between Stephens and Lincoln which will eventually lead to the end of the war. Meanwhile, fighting continues. President Lincoln has placed Major General William S. Rosecrans in charge of the defense of Nashville. Rosecrans works to cobble together another army to defend Tennessee from Stonewall Jackson’s onslaught. Rosecrans competently performs in this role, and after incorporating the survivors of Buell’s army into his force, he successfully withstands a siege by Jackson’s army which goes on until Jackson is forced by events elsewhere to abandon the siege and return to Alabama. One officer who distinguishes himself during this siege is a Confederate cavalry brigadier named Nathan Bedford Forrest, who is released by Jackson to bedevil the Union supply lines into Nashville. He defeats several Union forces which are sent to pursue him, each of them larger than his own, and gains a reputation for his tactical skill.
October 1862--On October 4, 1862, Vicksburg falls to Union forces under Major General Ulysses S. Grant. Meanwhile, at the demand of President Lincoln, Major General George B. McClellan advances south from Richmond and invades North Carolina. His army begins what will be a virtually unopposed march through the Carolinas, culminating in the capture of Charleston, South Carolina, in January 1862. Under McClellan’s leadership, Union foragers molest the local populace of the Carolinas as little as possible during their transit through those States (although, once in South Carolina, he is unable to prevent some pillaging and burning as troops full of hatred for South Carolina as the birthplace of the Confederacy vent their anger against the inhabitants of the State. Nevertheless, compared to the OTL march made by Sherman in 1864, South Carolina is comparatively unscathed by these activities).
November 1862--The Union Army of the Tennessee, under Ulysses S. Grant, begins advancing toward the new Confederate capital at Montgomery. General Robert E. Lee attempts to mount a defense, and orders very strong earthworks dug by his grumbling troops. President Stevens issues an order promoting Stonewall Jackson to Lt. General, while at the same time ordering him to abandon the siege of Nashville and return to Montgomery, to join the forces defending the city. Jackson abandons his siege on November 21, and retires southward. Major General Rosecrans cautiously pursues Jackson southward.
December 1862--Lt. General Jackson arrives back at Montgomery on December 8, 1862. General Robert E. Lee, upon his arrival, reorganizes the Army of Alabama, as the force defending Montgomery is called. Jackson is given command of the First Corps, while James Longstreet commands the Second. Lt. General John C. Breckinridge, one of the few surviving officers from Albert Sidney’s Johnston’s Army of Mississippi, is given command of the Third Corps. On December 19, the Union Army of the Tennessee, commanded by Ulysses S. Grant, arrives outside Montgomery. Major General Rosecrans and the Army of the Cumberland arrive six days later, on Christmas Day, 1862. The two armies lay siege to Montgomery.
December 1862-April 1863--The Siege of Montgomery.
January 1863--Charleston, South Carolina falls to the Union Army of the Potomac, commanded by George B. McClellan. McClellan goes into winter quarters there, and refuses to move, despite President Lincoln’s constant demands that he do so. However, McClellan is so popular, having captured both Richmond and Charleston, and taken the States of Virginia, North Carolina, and South Carolina out of the war, that President Lincoln does not dare to sack him. Lincoln can do nothing but grumble as the Army of the Potomac sits and does nothing.
February 1863--The Siege of Montgomery continues. The Union Army of the Potomac remains in winter quarters at Charleston.
March 1862--With the coming of Spring, Major General McClellan deigns to take his army out of winter slumber, and advances on Savannah, Georgia, capturing it by the end of the month. He then begins marching slowly toward the major Confederate railroad nexus and supply depot at Atlanta, Georgia. A cavalry raid led by George Armstrong Custer, who, following his performance at Richmond, has been promoted to command of a Cavalry Division, captures Augusta, Georgia, and destroys the Confederate powder works which is in the process of construction there.
April 1863...Negotiations between President Stevens and President Lincoln have been continuing. However, the military situation of the Confederacy has continued to deteriorate, and President Stevens no longer has any bargaining power. On April 12, 1863...exactly two years to the day after the war began at Fort Sumter, he sends another message to Lincoln offering the unconditional surrender of all Confederate forces. All he asks in return is amnesty, or if that cannot be had, the promise of a fair trial, for the Confederate leadership, and mercy for the Southern people during the process of Reconstruction which he knows must follow. To his surprise, he finds that his old friend, Abraham Lincoln, is all too willing to agree to these terms in order to immediately end the bloodshed. A ceasefire is declared as of midnight, April 12, 1863. General Robert E. Lee, on behalf of the President, officially surrenders all Confederate forces the next day. The war is over.