In 1592, a quarantine hospital known as the Lazzaretto was built during an outbreak of the plague. The hospital was made of wooden huts, and it was pulled down a year later after the disease had subsided. In 1643, during the reign of Grandmaster Lascaris, the Order of Saint John exchanged the island with the church for some land in Rabat and built a permanent Lazzaretto in an attempt to control the periodic influx of plague and cholera on board visiting ships. It was initially used as a quarantine centre where passengers from quarantined ships were taken. The hospital was subsequently improved during the reigns of Grandmasters Cotoner, Carafa and de Vilhena.