 Complete the following phrase:  The date of this tower is unknown and it pre-dates many other towers that were built around the Bay of Gibraltar and south of Algeciras as batteries and watchtowers. This tower was used by the Admiral Egidio Boccanegra in the 14th century during the Siege of Algeciras 1342-1344. The tower appears on a map of 1608 and it was improved after 1704 following the 