Ireland became a member of the United Nations in 1955. The first contribution to peacekeeping was in 1958 when Army officers were assigned to the United Nations Observation Group in Lebanon (UNOGIL). Since 1958 the Defence Forces have had a continuous presence on armed United Nations peacekeeping operations, except between May 1974 to May 1978 (although they did retain overseas unarmed observer missions during this period). The first armed peacekeeping mission was to the Operation des Nations Unies au Congo (ONUC) in 1960. During the ONUC mission, a company from the Irish Army were involved in a battle at Jadotville, in which the Irish held-out against a larger Katangese force. A memorial to Irish personnel who served as United Nations peacekeepers was unveiled in 2009 in the town of Fermoy, recording that there was a total of ninety Irish fatalities while on active service with the UN until that date.