Stephen the Posthumous was the posthumous son of King Andrew II of Hungary by his third wife, Beatrice d'Este. He was regarded as bastard son of infidelity by his much older half-brothers, including King Béla IV of Hungary, and was not allowed to receive ducal revenues from Hungary to which he would have been entitled as son of a Hungarian king.
Queen Beatrice d'Este, Stephen's mother
Stephen's second wife Tomasina Morosini with their son Andrew, future King of Hungary
Andrew II, also known as Andrew of Jerusalem, was King of Hungary and Croatia between 1205 and 1235. He ruled the Principality of Halych from 1188 until 1189/1190, and again between 1208/1209 and 1210. He was the younger son of Béla III of Hungary, who entrusted him with the administration of the newly conquered Principality of Halych in 1188. Andrew's rule was unpopular, and the boyars expelled him. Béla III willed property and money to Andrew, obliging him to lead a crusade to the Holy Land. Instead, Andrew forced his elder brother, King Emeric of Hungary, to cede Croatia and Dalmatia as an appanage to him in 1197. The following year, Andrew occupied Hum.
Seal of Andrew II, 1224
Andrew II depicted in Illuminated Chronicle
Andrew II depicted in Chronica Hungarorum
Gertrude of Merania and Andrew depicted in the 13th-century Landgrafenpsalter from the Landgraviate of Thuringia