In 1207 the Ghisi brothers captured the island and built the Bourtzi, a small Venetian-styled fortress similar to the Bourtzi in Nafplio, on an islet just out of Skiathos Town, to protect the capital from the pirates. But the Bourtzi was ineffective in protecting the population and in the mid-14th century the inhabitants moved the capital from the ancient site that lay where modern Skiathos Town is to Kastro (the Greek word for castle), located on a high rock, overlooking a steep cliff above the sea at the northernmost part of the island. The island returned to Byzantine control in the 1270s, and remained in Byzantine hands until after the Fall of Constantinople in 1453, when it passed to the Republic of Venice. Like the rest of the Northern Sporades, Skiathos was conquered by the Ottoman admiral Hayreddin Barbarossa in 1538.