Sugar cane cultivation in Barbados began in the 1640s, after its introduction in 1637 by Pieter Blower. Initially, rum was produced but by 1642, sugar was the focus of the industry. As it developed into the main commercial enterprise, Barbados was divided into large plantation estates which replaced the small holdings of the early English settlers as the wealthy planters pushed out the poorer. Some of the displaced farmers relocated to the English colonies in North America, most notably South Carolina. To work the plantations, black Africans – primarily from West Africa – were imported as slaves in such numbers that there were three for every one planter. Increasingly after 1750 the plantations were owned by absentee landlords living in Britain and operated by hired managers. The slave trade ceased in 1807 and slaves were emancipated in 1834. Persecuted Catholics from Ireland also worked the plantations. Life expectancy of slaves was short and replacements were purchased annually.