Mortars have existed for hundreds of years. They were first used in sieges. A European description of the Siege of Belgrade (1456) by Giovanni da Tagliacozzo says that the Ottoman Turks used seven mortars that fired "stone shots one Italian mile high". The speed of these was said to be very slow. It was also said that men could be prevented from being injured by putting observers out who warned the troops of what angle the mortars were firing at.