The Army Ranger Wing roles are divided between wartime special operations ( " Green Role " ) and anti-terrorism ( " Black Role " ) , the latter known formally as military Aid to the Civil Power ( ATCP ) : - '' ' Offensive operations behind enemy lines ' '' '' ' Defensive operations ' '' In the late 1960s , the Defence Forces established Special Assault Groups ( SAG ) in the Army to meet security challenges on the border with Northern Ireland . A number of Army officers attended the United States Army Ranger School in Fort Benning , Georgia who returned to conduct Army Ranger courses in Ireland with the first held in 1969 . Among its founding officers was later-to-be Chief of Staff Lieutenant General Dermot Earley . Special Assault Groups were formed comprising 40 Rangers trained in all arms , engineering and ordnance techniques . By the mid 1970s , the Defence Forces had over 300 Rangers who conducted support operations on the request of the Garda Síochána . Students on these courses were selected from among all ranks and units of the Army , Naval Service and Air Corps . The courses improved standards of physical endurance , marksmanship , individual military skills and small unit tactics . In December 1977 , the Garda Síochána formed a counter terrorist unit named the Special Task Force ( STF ) to operate in border regions that was later to become the Emergency Response Unit . In 1978 , following an assessment of the SAG , it was decided to consolidate the Rangers into a new special forces unit with a counter terrorist capability following an increase in international and national terrorism , such as the 1972 Munich massacre in Germany ( then West Germany ) and a number of hostage-takings by the Provisional IRA ( such as the Balcombe Street siege )
Munich massacre
Munich massacre
Army Ranger Wing