Perhaps the Komnenids could survive in power longer by delaying the Battle of Myriokephalon in 1176. In OTL, this comparatively minor defeat greatly depressed the Emperor Manuel Komnenos (then aged fifty eight) and led to the loss of his once active personality, and finally his death four years later. If Myriokephalon is avoided or won, perhaps Manuel can survive for say six years longer than in OTL, dying in 1186, allowing his son Alexios II to avoid a period of regency, and come to the throne of a relatively intact Empire in 1186. Alexios proves to be a relatively competent Emperor, subdues the Bulgar rebellion, manages the Third Crusade less horribly than the Angeloi did in OTL, and reigns until the 1220s. His successors deal with the Mongols deftly, and win back Anatolia once the Turks are broken. The Komnenid dynasty is then roughly secured.