Complex sentence: In 1497, the island was (along with Inchgarvie) used as an isolated refuge for victims of syphilis and in 1589, history repeated itself when the island was used to quarantine the passengers of a plague-ridden ship.
Split into simpler sentences: In 1497, the island was (along with Inchgarvie) used as an isolated refuge for victims of syphilis. In 1589, history repeated itself, and the island was used to quarantine the passengers of a plague-ridden ship.