Upward Mobility

Read this bit first: only the diplomatic "Claim Liege's Title" interaction counts. The Claim Throne scheme does not, and winning a claim war doesn't either - there are confirmed reports of players winning the war at higher legitimacy and getting nothing. You don't even need to fight; the claim itself fires it. The wiki setup: in 867, replace the duke of the Doolani Amirate (in the Habbari Sultanate) with a custom Just + Sayyid diplomat - you start at legitimacy 4 against a liege on 1. Farm prestige with hunts and feasts to the 1500 the interaction costs, use it, done. Needs Legends of the Dead.