 If his uncle had lived a few years longer, Yohannan's succession would probably have been assured, but the patriarch was among the victims of a plague which swept through the Mosul district in 1778, and died in the village of Alqosh on 29 April 1778.On the following day his nephews Ishoyahb and Yohannan both made Catholic professions of faith and were reconciled.Despite the late patriarch's preference the Latin missionaries supported Ishoyahb, who shortly afterwards succeeded his uncle as patriarch, taking the name Eliya XIII Ishoyahb, without open opposition from the young Yohannan.