Who married João III Ducas Vatatzes?

João III Ducas Vatatzes (em grego: Ιωάννης Γ΄ Δούκας Βατάτζης, Iōannēs III Doukas Batatzēs) (1192 – 3 de Novembro de 1254), foi imperador bizantino que reinou em Niceia (1221–1254).

Irene Laskarina (c. 1194-9 – 1240) (Greek: Εἰρήνη Λασκαρίνα, romanized: Eirēnē Laskarina) was Empress consort of Nicaea. She was a daughter of Theodore I Komnenos Laskaris, emperor of Nicaea and Anna Komnene Angelina. Her maternal grandparents were Alexios III Angelos and Euphrosyne Doukaina Kamatera. Her sister, Maria Laskarina, married Béla IV of Hungary.

In 1204, during Irene Laskarina's childhood, the city of Constantinople fell to a Crusader army during the Sack of Constantinople. Much of the nobility, including Irene's family, fled, and re-established a capitol in Nicaea; this became the Nicaean empire.

Irene first married the general Andronikos Palaiologos, and after his death became the wife of Theodore's designated successor, the future John III Doukas Vatatzes in 1212. They had a son, the future Theodore II Doukas Laskaris. After the latter's birth, she fell from a horse and was so badly injured that she was unable to have any more children. She retired to a convent, taking the monastic name Eugenia, and died there in summer of 1240, some fourteen years before her husband.

Irene is praised by historians for her modesty and prudence and is said to have brought about by her example a considerable improvement in the morals of her nation.

Anna av Hohenstaufen (tyska: Konstanze von Staufen), född 1230, död april 1307 i Valencia i Spanien, var en nicaeansk kejsarinna genom giftermålet med kejsar Johannes III Ducas.