Britain's Queen Elizabeth has engaged in an historic handshake with a former leader of the separatist group that waged a bloody decades-long fight for Northern Ireland's independence from British rule.

The handshake between the monarch and Martin McGuinness, a former leader of the Irish Republican Army-turned deputy first minister of Northern Ireland, took place Wednesday at the start of a private social event in a Belfast theater. The two were expected to exchange a public handshake after the event.

The historic event symbolizes the lasting peace in the British territory since the 1998 Good Friday accords, which ended the 30-year insurgency waged by the pro-Catholic IRA against troops from Protestant Britain. The insurgency claimed more than 3,500 lives, including that of Queen Elizabeth's cousin, World War Two hero Lord Mountbatten. Mountbatten was assassinated in 1979 by an IRA bomb planted on his boat.

Sinn Fein, the IRA's political arm, continues to oppose British rule in Northern Ireland.

Queen Elizabeth and her husband, Prince Philip, arrived in Northern Ireland Tuesday for the start of a two-day visit marking her 60th year on the British throne. She visited the small town Enniskillen, where she met with relatives of people killed in an IRA bomb attack 25 years ago, and attended services at the town's Catholic church, the first time she has done so in her 20 visits to Northern Ireland.