sentences:  Hulagu promised the restoration of Jerusalem to the Christians, but also still insisted on Mongol sovereignty, in the Mongols' quest for conquering the world.It is unclear whether or not King Louis actually received the letter, but at some point it was transmitted to Pope Urban, who answered in a similar way as his predecessors.In his papal bull "Exultavit cor nostrum", Urban congratulated Hulagu on his expression of goodwill towards the Christian faith, and encouraged him to convert to Christianity.