Mare clausum defended a "Mare clausum" policy during the age of discovery. This was soon challenged by other European nations. From 30 BC to 117 AD the Roman Empire came to surround the Mediterranean by controlling most of its coasts. Romans started then to name this sea "mare nostrum" (Latin for "our sea"). At those times the period between November and March was considered the most dangerous for navigation, so it was declared ""mare clausum"" (closed sea), although bans on navigation were probably never enforced. In classical law the ocean was not territorial. However, since the Middle Ages maritime republics like the
Exultavit cor nostrum Exultavit cor nostrum Exultavit cor nostrum is a letter, also known as a Papal bull, from Pope Urban IV to the Mongol Ilkhanate leader Hulagu in 1263/1264. The letter was evidently in response to a message brought to Urban by John the Hungarian, who claimed to be the Mongol envoy (it was not uncommon for individuals to present themselves as envoys, even when they were not). According to John, Hulagu desired to become a Christian, and requested that Urban send a representative who would help to baptise him. Pope Urban responded with the "Exultavit", which indicated that Urban had heard