<Table> <Tr> <Td> </Td> <Td> It has been suggested that Partitionism be merged into this article . (Discuss) Proposed since April 2017 . </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> It has been suggested that Partitionism be merged into this article . (Discuss) Proposed since April 2017 . </Td> </Tr> <P> The partition of Ireland (Irish: críochdheighilt na hÉireann) was the division of the island of Ireland into two distinct jurisdictions, Northern Ireland and Southern Ireland . It took place on 3 May 1921 under the Government of Ireland Act 1920 . Today the former is still known as Northern Ireland and forms part of the United Kingdom, while the latter is now a sovereign state also named Ireland and sometimes called the Republic of Ireland . </P> <P> The Act of 1920 was intended to create two self - governing territories within Ireland, with both remaining within the United Kingdom . It also contained provisions for co-operation between the two territories and for the eventual reunification of Ireland . However, in 1922, following the War of Independence and the Anglo - Irish Treaty, the southern part became the Irish Free State, while Northern Ireland exercised its option to remain in the United Kingdom . </P>

When did northern ireland and southern ireland separate