The dogal Republic of Venice purchased the area of Butrint including Corfu from the Angevins in 1386; however, the Venetian merchants were principally interested in Corfu and Buthrotum once again declined. The Venetians began to invest in Butrint in the late 15th century, which seems a likely date for the Triangular Fortress construction. Musket ports opened at both ground level and along the parapet walk. Vaulted storerooms inside the fort carried artillery platforms above to train cannon on the approach to Butrint up the Vivari Channel. In 1798, however, the fortress was slighted by General Chabot, the commander of the garrison of the French dependency of Corfu.
Triangular Fortress takes the form of an irregular triangle with a tower at each point. Originally, it stood on an island in a pre-canalised river mouth, protected by an outer siege work or ravelin (a crescent-shaped defensive wall).The keystone of one the interior buildings bears a relief of the Lion of St. Mark, the symbol of the Republic of Venice.
References:The Broch of Clickimin is a large and well preserved, though somewhat restored broch near Lerwick. Originally built on an island in Clickimin Loch (now increased in size by silting and drainage), it was approached by a stone causeway. The water-level in the loch was reduced in 1874, leaving the broch high and dry. The broch is situated within a walled enclosure and, unusually for brochs, features a large 'blockhouse' between the opening in the enclosure and the broch itself. Another unusual feature is a stone slab featuring sculptured footprints, located in the causeway which approached the site. Situated across the loch is the Clickimin Leisure Centre.