The Great Famine of Ireland (1845–1849) saw the city's largest immigrant influx occur, with the government forced to construct a quarantine station and hospital on Partridge Island at the mouth of the harbour to handle the new arrivals. These immigrants changed the character of the city and surrounding region so that in addition to its Loyalist-Protestant heritage, there was a new Irish-Catholic culture as well. Between 1845 and 1847, approximately 30,000 Irish arrived in Saint John, more than doubling the population of the city. During this period, Saint John was second only to Grosse Isle, Quebec as the busiest port of entry to Canada for Irish immigrants. The Roman Catholic population was largely impoverished and uneducated.