Plantations in 16th and 17th century Ireland were the confiscation of land by the English crown and the colonisation of this land with settlers from England and the Scottish Lowlands.
They followed smaller-scale immigration to Ireland as far back as the 12th century, which had resulted in a distinct ethnicity in Ireland known as the Old English.
The 16th century plantations were established throughout the country by the confiscation of lands occupied by Gaelic clans and Hiberno-Norman dynasties, but principally in the provinces of Munster and Ulster. The lands were then granted by Crown authority to colonists ("planters") from England. This process began during the reign of Henry VIII and continued under Mary I and Elizabeth I. It was accelerated under James I, Charles I and Oliver Cromwell, and in their time the planters also came from Scotland.
The early plantations in the 16th century tended to be based on small "exemplary" colonies. The later plantations were based on mass confiscations of land from Irish landowners and the subsequent importation of large numbers of settlers from England and Wales, later also from Scotland.
The final official plantations took place under the English Commonwealth and Cromwell's Protectorate during the 1650s, when thousands of Parliamentarian soldiers were settled in Ireland. Apart from the plantations, significant migration into Ireland continued well into the 18th century, from both Great Britain and continental Europe.
The plantations changed the demography of Ireland by creating large communities with a British and Protestant identity. These communities replaced the older Catholic ruling class, which shared with the general population a common Irish identity and set of political attitudes. The physical and economic nature of Irish society was also changed, as new concepts of ownership, trade and credit were introduced. These changes led to the creation of a Protestant ruling class, which secured the authority of Crown government in Ireland during the 17th century.