Иоанн III Дука Ватац
John III Doukas Vatatzes, Latinized as Ducas Vatatzes (, "Iōannēs Doukas Vatatzēs", c. 1193, Didymoteicho – 3 November 1254, Nymphaion), was Emperor of Nicaea from 1222 to 1254. He was succeeded by his son, known as Theodore II Laskaris.