On April 20, 1434, Đurađ Branković's youngest daughter Katarina and Ulrich II of Celje were wed in the new fortress. This marriage stressed the friendly relations the Despot had with the Ottoman Porte, although Ulrich's kinship with the Queen of Hungary implied an increased Serbo-Hungarian alliance. As a result, Vizier Mehmet Saridže-pasha arrived in Smederevo in mid-1434 with a message from Edirne. It stated that Serbia's safety from the Ottoman Empire could only be guaranteed through the marriage of Branković's older daughter to Sultan Murad II. After much deliberation, the council convoked at the palace conceded, and arrangements were made for Mara to be engaged to the Sultan. That autumn, Murad sent several of his "most famous viziers" to retrieve his fiancée.