The Frankish peoples never unite under a common interest, as such, no Germanic elite arises in northern Gaul, instead, the centre of power remains in the increasingly Romanised south.
The Roman Empire collapses, a few decades later than OTL, and northern Gaul becomes a patchwork of small, tribal states. While southern Gaul eventually becomes a centralised kingdom.
Following the Islamic conquest of Spain, the Kingdom of Gaul starts to become increasingly Gothicised. However, this is not a smooth time for Gaul, and much of the earlier centralising work is undone by warlords.
Meanwhile, the Magyars have spent the past few centuries gradually migrating further into Central Europe.
Around the dawn of the 2nd millenium, the Magyars convert to Catholicism, and, through a series of pious leaders, their relationship with the papacy becomes increasingly tight.
1100s: The King of the Magyars, (who has by now settled his people along the southern Rhine), is declared Emperor of the Christians (TTL equivilant of Holy Roman Emperor).
1200s: The small states of northern Gaul, who had previously owed vassalage to numerous surrounding states, begin to pledge themselves to the Christian Emperor.
Mid-1300s: A dynastic union merges the Kingdom of Gaul with the Christian Empire of Magyarland. Aside from this, the Empire held vassalage from the English Channel to northern Spain and Italy.
1400s: A reforming Emperor seeks to centralise his Empire, essentially annexing the formerly independent vassals into one Empire, which now controls most of Western Europe. A new system of aristocratic governorates is established, many new governors are recruited from throughout Europe, (from Poland, from Sicilia, from Scotland, from Romania... a wide number of states, whose only similarity is their alliance with the Empire).
1500s: The Christian Empire of Magyar-Gallica patronises a renown explorer to sail West to find a trade route to Asia. The explorer discovers Újguilágge, (the New World). The Empire begins sending Konkvisztádors (conquerors) to Újguilágge.
In a Europe where dynasticism rules absolutely, the Empire's ability to grant deeds of land to powerful nobles was invaluable. The weak German states to the Empire's east were weakened furthermore when the German kinds discovered that many of their barons on the ground had been bribed with Újguilággean lands.
However, aristocrats from within the Empire formed the plurality of the colonising interests.
One such colonial barony belonged to the Guerbőczy family. Their colony was established on the western shore of the OTL Gulf of Mexico. The colony was named Tészág, because it was believed that the colony's climate would be ideal for the growing of a Chinese plant known as Té, (which could be brewed to create a beverage which was particularly popular in the Imperial courts).
In the late 1600s, a religious revolution took place in north-eastern Europe. Theologians, aswell as local people, became increasingly annoyed by the constant meddling of the theocratic Christian Empire of Magyar-Gallica. Catholic, pro-Imperial lords attempted to crush the so-called heresies. This began to cause a great deal of conflict around Europe and so, the period of peace that the Christian Empire had resided over for the past 200 years began to collapse.
The 18th and 19th Centuries were defined by their almost constant warfare. Great powers arose, (notably the Netherleague, the Commonwealth of Great Britain and the Russian Empire), and, great powers fell. Following a series of devastating losses, the Christian Empire was disbanded - its successor states were Britténig, the Republic of Magyarland, and the Kingdom of Gaul. Following the collapse, the Kingdom of Iberia pushed its frontiers up to the Pyrenees, and the Kingdom of Italy expanded up to the Alps.
Meanwhile, across the Atlantic, the Americas have been left much less united than in OTL. Several dozen states exist in North America alone, many with different languages.
Among them, the Republic of Tészág. A secular republic (who's people are predominantly non-Catholic Christians). The primary language in the republic is Magyar, but there are significant Gallic and Hispanic minorities.