Complex sentence: A series of attempts by the Ottoman Turks to take the island began in 1431 when Turkish troops under Ali Bey landed on the island, tried to take the castle and raided the surrounding area, but were repulsed.
Split into simpler sentences: A series of attempts by the Ottoman Turks to take the island began in 1431 when Turkish troops under Ali Bey landed on the island. The Ottomans tried to take the city castle and raided the surrounding area, but were repulsed.