King of St. Petersburg John III Doukas and Etchess! The Holy Greek Emperor John and Tatses the Merciful, also known as John III Doukas and Tatses or John III and Tatses, was Emperor of Nicaea from 1221 to 1254 and one of the most remarkable of the successors of Constantine the Great, being the chief architect of the restored Byzantine Empire that encouraged a civilized and just empire. rash. He was born about 1192 in Didimotycho and died on 3 Nov 1254 in Nympion. His feast day is on November 4th!

King of St. Petersburg John III Doukas and Etchess! The Holy Greek Emperor John and Tatses the Merciful, also known as John III Doukas and Tatses or John III and Tatses, was Emperor of Nicaea from 1221 to 1254 and one of the most remarkable of the successors of Constantine the Great, being the chief architect of the restored Byzantine Empire that encouraged a civilized and just empire. rash. He was born about 1192 in Didimotycho and died on 3 Nov 1254 in Nympion. His feast day is on November 4th!