Fort Jesus Fort Jesus ( Forte Jesus de Mombaça ) is a Portuguese fort built in 1591 by order of King Philip I of Portugal ( King Philip II of Spain ) , then ruler of the joint Portuguese and Spanish Kingdoms , located on Mombasa Island to guard the Old Port of Mombasa , Kenya . It was built in the shape of a man ( viewed from the air ) , and was given the name of Jesus . In 2011 , the fort was declared a World Heritage Site by UNESCO , highlighted as one of the most outstanding and well preserved examples of 16th - century Portuguese military fortifications . Overview . Between 1631 and 1875 the fort was won and lost nine times by the nations contesting control of Kenya . The Omanis took the fort in 1698 after a notable siege of almost three years . It was declared a historical monument in 1958 . Today it houses a museum . The fort was designed by a Milanese architect , Giovanni Battista Cairati , who was the Chief Architect for Portuguese possessions in the East . It was the first European - style fort constructed outside of Europe designed to resist cannon fire . Today , it is one of the finest examples of 16th - century Portuguese military architecture , which has been influenced and changed by both the Omani Arabs and the British . The fort quickly became a vital possession for anyone with the intention of controlling Mombasa Island or the surrounding areas of trade . When the British colonised Kenya , they used it as a prison , until 1958 , when they converted it into a historical monument . James Kirkman was then assigned to excavate the monument , which he did ( with a large use of external historical documents ) from 1958 to 1971 . The architecture of the fort represents the rough outline of a person lying on their back , with the head towards the sea . The height of the walls is 18 meters . The original Portuguese fort had a height of 15 meters , but the much taller Oman Arabs added 3 metres upon capturing the fort . The fort combines Portuguese , Arab , and British elements ; these being the major powers that held it at different times in history . The Portuguese and British presence is preserved in the presence of their respective cannons . The Portuguese cannons had a range of 200 meters and are longer than the British cannons which had a range of 300 meters . Oman Arabs marked their occupancy with numerous Koran inscriptions into the wooden door posts and ceiling beams . The Muslim tradition of 5 pillars is also portrayed throughout the fort , with a former meeting hall supported by five stone pillars to the ceiling . Some of the historical structures still standing in the fort include Oman House , which was the house for Sultan who governed the East African coast . Others are an open water cistern by the Portuguese for harvesting rain water , and a 76 - foot deep well sank by the Arabs , but whose water was too salty to be used for anything but washing . The fort was declared a World Heritage site by UNESCO in 2011 . Fort Jesus today . Fort Jesus is now a popular destination for foreign and local tourists . As well as a tourist destination the Fort is important as a host for numerous research programs , a Conservation Lab , and Education Department and an Old Town Conservation Office .