On August 27, 1979, Lord Louis Mountbatten is killed when Irish Republican Army terrorists who detonate a bomb hidden on his fishing vessel Shadow V. Mountbatten, a war hero, elder statesman, and second cousin of Queen Elizabeth II, was spending the day with his family in Donegal Bay off Ireland’s northwest coast when the bomb exploded. Three others were killed in the attack, including Mountbatten’s 14-year-old grandson, Nicholas. Later that day, an IRA bombing attack on land killed 18 British paratroopers in County Down, Northern Ireland. The assassination of Mountbatten was the first blow struck against the British royal family by the IRA during its long terrorist campaign to drive the British out of Northern Ireland and unite it with the Republic of Ireland to the south. The attack convinced Margaret Thatcher’s government to take a hard-line stance against the terrorist organization.

Louis Mountbatten, the son of Prince Louis of Battenberg and a great-grandson of Queen Victoria, entered the Royal Navy in 1913, when he was in his early teens. He saw service during World War I and World War II. In 1947, he was appointed the last viceroy of India, and he conducted the negotiations that led to independence for India and Pakistan later that year. He held various high naval posts in the 1950s and served as chief of the United Kingdom Defense Staff and chairman of the Chiefs of Staff Committee. Meanwhile, he was made Viscount Mountbatten of Burma and a first earl. He was the uncle of Philip Mountbatten and introduced Philip to the future Queen Elizabeth. He later encouraged the marriage of the two distant cousins and became godfather and mentor to their first born, Charles, Prince of Wales.

Made governor and then lord lieutenant of the Isle of Wight in his retirement, Lord Mountbatten was a respected and beloved member of the royal family. His assassination was perhaps the most shocking of all horrors inflicted by the IRA against the United Kingdom. The IRA immediately claimed responsibility for the attack, saying it detonated the bomb by remote control from the coast. IRA member Thomas McMahon was later arrested and convicted of preparing and planting the bomb that destroyed Mountbatten’s boat. He was a leader of the IRA’s notorious South Armagh Brigade, which killed more than 100 British soldiers. He was one of the first IRA members to be sent to Libya to train with detonators and timing devices and was an expert in explosives. Authorities believe the Mountbatten assassination was the work of many people, but McMahon was the only individual convicted. Sentenced to life in prison, he was released in 1998 along with other IRA and Unionist terrorists under a controversial provision of the Good Friday Agreement, Northern Ireland’s peace deal.

Michael Thomas Barry is a columnist for CrimeMagazine.com and pens the daily column “On this date in crime history. He is also the author of Murder & Mayhem 52 Crimes that Shocked Early California (2012) and Great Britain’s Royal Tombs (2012).