John III Doukas Vatatzes, Byzantine emperor (b. 1193)
John III Doukas Vatatzes, Latinized as Ducas Vatatzes (Greek: Ιωάννης Δούκας Βατάτζης, Iōannēs Doukas Vatatzēs, c. 1193 – 3 November 1254), was Emperor of Nicaea from 1222 to 1254. He was succeeded by his son, known as Theodore II Laskaris.