The regiment that the 6th Battalion, Ulster Defence Regiment grouped into had who as their oldest predecessor?
6th Battalion, Ulster Defence Regiment The 6th (County Tyrone) Battalion, Ulster Defence Regiment (6 UDR) was formed in 1970 as part of the seven original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was, along with the rest of the regiment, amalgamated with the Royal Irish Rangers in 1992 to form the Royal Irish Regiment.
East Yorkshire Regiment The East Yorkshire Regiment was a line infantry regiment of the British Army, first raised in 1685 as Sir William Clifton's Regiment of Foot and later renamed the 15th Regiment of Foot. It saw service for three centuries, before being amalgamated with the West Yorkshire Regiment (Prince of Wales's Own) to form the Prince of Wales's Own Regiment of Yorkshire in 1958. Subsequently, the regiment amalgamated with the Green Howards and the Duke of Wellington's Regiment (West Riding) to form the Yorkshire Regiment (14th/15th, 19th and 33rd/76th Foot) on 6 June 2006.