Eliasz Aleksander Ostrogski (1510âÂÂ1539), also known as Illia Ostrogski, was the only son of Konstanty Ostrogski from his first marriage with Tatiana Koretska. He was starost of Bratslav and Vinnytsia.
When he was 13, his father Konstanty agreed with Jerzy Radziwià Âà  to wed Illia and Anna Elà ¼bieta Radziwià Âà Â. In 1537, Illia cancelled the agreement and was offered the hand of Barbara Radziwià Âà Â, younger sister of Anna Elà ¼bieta. Illia refused and married his love Beata Koà Âcielecka.
On 3 February 1539 Illia married Beata Koà Âcielecka, rumoured to be an illegitimate daughter of King Sigismund I the Old and Katarzyna Telniczanka. The ceremony took place at Wawel Castle, one day after the wedding of Isabella Jagiellon and Hungarian King John Zápolya. At that time Illia converted to Roman Catholicism. The wedding was lavish and included tournaments. Illia duelled with Sigismund II Augustus and was defeated. He was thrown off his horse and "beaten so badly, that for 6 months was complaining". The injuries possibly became the reason of his death on 15 August 1539.
Illia's only daughter, Elizaveta (Halszka), born after his death. According to his testament, Elizaveta was placed under protection of Sigismund II Augustus.