 Complete the following phrase:  In 1097, the Crusader armies assembled at Constantinople having traveled in groups eastward through Europe. Alexios I, who had requested only some western knights to serve as mercenaries to help fight the Seljuk Turks, blockaded these armies in the city and would not permit them to leave until their leaders swore oaths promising to restore to the Empire any land formerly belonging to it that they might conquer on the way to Jerusalem. The Crusaders eventually swore these oaths, individually rather than as a group. In return, Alexios gave them guides and a military escort. The Crusaders were however exasperated by Byzantine tactics, such as negotiating the surrender of Nicaea from the Seljuks while it was still under 