New conflict emerged in 1453 upon the death of Petar Talovac, who had governed Croatia proper as ban on behalf of the Hungarian king. Both Thomas and his recently widowed father-in-law wished to gain control of Talovac's allodial land by offering marriage to his widow, Hedwig Garai; Kosača proposed himself, while Thomas suggested his son Stephen. Kosača invited Turks to Bosnia in autumn, but neither prevailed as Venice moved in to protect Talovac's heirs. They then made peace, realizing that the Ottomans, who had just stunned Europe by conquering Constantinople, would soon be at their gates as well. Another concern was the end of regency for the hitherto underage Hungarian king Ladislaus the Posthumous, which decreased the influence of Thomas' friend János Hunyadi, and led to the rise of Ulrich of Celje, who was supported by Kosača. After Ladislaus made Ulrich the new Ban of Croatia, the latter started seizing control of Croatian towns, which met strong opposition from Thomas. The Bosnian king feared that Ulrich would take Talovac's land and have his territory border Kosača's. Not wishing to break peace with his father-in-law yet again, the King turned to Venice for help.