Aethelred I lives long enough to deny Alfred the throne

[acgoldis]

According to a Website on the British royal family,

Born at Wantage, Berkshire, in 849, Alfred was the fifth son of Aethelwulf, king of the West Saxons. At their father's behest and by mutual agreement, Alfred's elder brothers succeeded to the kingship in turn, rather than endanger the kingdom by passing it to under-age children at a time when the country was threatened by worsening Viking raids from Denmark.

Alfred had to get through three brothers to reach the throne. Now as it turns out his youngest older brother (his predecessor) already had infant children at the time he died.
These children were passed over for the throne as they were minors, so Alfred got it. What happens if this brother lives 20 years longer, giving the children a chance to grow up and succeed him? In that case, Alfred is left without a throne.

 

[perdu42]

What happens if this brother lives 20 years longer, giving the children a chance to grow up and succeed him?

Except the agreement – and admittedly Asser’s description of said advisory leaves a lot to be desired – that Æthelwulf’s sons would succeed each other in turn seems to have had little to do with worsening Viking raids.
In 868, Alfred extracted from his brother Æthelred a modification of the agreement ie Alfred was explicitly recognized as heir apparent. Exact dating is problematic (to say the least) but the timing of this seems to coincide with the probable birth of Æthelwold. Of course agreements can be changed but it seems likely Alfred will succeed his brother no matter… a new agreement will likely be negotiated on who succeeds Alfred which may lead to a reversal of OTL ie Edward raising rebellion against his cousin Æthelwold.

Of course this leaves aside the larger existential question of the Viking raids and whether a Æthelred led Wessex can pull off Alfred’s feats.