and seventeenth centuries. Gedi was abandoned by the middle of the seventeenth century. The presence of the Portuguese from the sixteenth century has been considered one of the primary factors in Gedi's eventual abandonment with their attempts to monopolize trade and due to armed intervention. However, a drop in the water table seen with the deepening of the well next to the Great Mosque, a Wazimba raid along the coast in 1589, and Oromo migrations and raids from Somalia may have been additional factors in the abandonment of Gedi and most of the mainland coastal sites north of Mombasa. Architecture The Gedi ruins make up a site consisting of that lies in the primeval Arabuko-Sokoke Forest. The ancient town at Gedi is divided by two walls, with an outer wall enclosing and an inner wall enclosing . Within the inner wall there are two mosques, a palace or Sheikh's house, four large houses, several clustered houses, and four large pillar tombs comprising the urban core. The inner wall also encloses four other houses and three other mosques. Between the inner and outer walls few stone structures have been identified with the exception of two mosques. Immediately beyond the outer wall there is one mosque and several other unidentified structures. In addition to being divided by the inner and outer walls, which created an urban core occupied by the site's foremost buildings and areas of occupation between and outside of the outer wall, Gedi has a well-established infrastructure. Gedi's structures appear to be formally arranged in accordance with streets laid out in a grid pattern. Additionally the site contained sumps to collect storm water and lavatories in many of its primary buildings. The majority of Gedi's structures were domestic residences made of thatched-roofed mud buildings concentrated between the outer and inner walls; however, the only buildings that survived to the present were constructed using coral stones extracted from the Indian Ocean. Although several of the buildings predate the fourteenth century, coral became a more common construction material for important structures and elite residences during that time period. All of the buildings at Gedi are single-story structures. The walls and other coral structures were constructed in a similar manner using lime mortar, with most foundations no greater than one foot in depth and filled with stones. Where foundations were used, they tended to be no wider than the wall they supported. There