Lord Louis Mountbatten is killed on August 27, 1979, when Provisional Irish Republican Army (IRA) terrorists detonate a 50-pound bomb hidden on his fishing vessel, Shadow V. Mountbatten, a war hero, elder statesman, and second cousin of Queen Elizabeth II, is spending the day with his family in Donegal Bay off Ireland’s northwest coast when the bomb explodes. Three others are killed in the attack, including Mountbatten’s 14-year-old grandson, Nicholas. Later that day, an IRA bombing attack on land kills 18 British paratroopers in County Down, Northern Ireland in what becomes known as the Warrenpoint ambush.

The assassination of Mountbatten is 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 hardens the hearts of many British against the IRA and convinces Prime Minister Margaret Thatcher’s government to take a hardline stance against the terrorist organization.

Mountbatten, the son of Prince Louis of Battenberg and a great-grandson of Queen Victoria I, enters the Royal Navy in 1913, when he is in his early teens. He sees service during World War I and at the outbreak of World War II is commander of the 5th Destroyer Flotilla. His destroyer, the HMS Kelly, is sunk during the Battle of Crete early in the war. In 1941, he commands an aircraft carrier, and in 1942 he is named Chief of Combined Operations Headquarters. From this position, he is appointed Supreme Allied Commander for South East Asia Command in 1943 and successfully conducts the campaign against Japan that leads to the recapture of Burma.

In 1947, Mountbatten is appointed the last Viceroy of India, and he conducts the negotiations that lead to independence for India and Pakistan later that year. He holds various high naval posts in the 1950s and serves as chief of the United Kingdom Defense Staff and chairman of the Chiefs of Staff Committee. Meanwhile, he is made Viscount Mountbatten of Burma and a first earl. He is the uncle of Philip Mountbatten and introduces Philip to the future Queen Elizabeth. He later encourages the marriage of the two distant cousins and becomes 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, Mountbatten is a respected and beloved member of the royal family. His assassination is perhaps the most shocking of all horrors inflicted by the IRA against the United Kingdom. In addition to his grandson Nicholas, 15-year-old boat hand Paul Maxwell and the Dowager Lady Brabourne, Nicholas’ grandmother, are also killed. Mountbatten’s grandson Timothy, Nicholas’ twin brother, is injured as is his daughter, Lady Brabourne, and the twins’ father, Lord Brabourne.

The IRA immediately claims responsibility for the attack, saying it detonated the bomb by remote control from the coast. It also takes responsibility for the same-day bombing attack against British troops in County Down, which claims eighteen lives.

IRA member Thomas McMahon is later arrested and convicted of preparing and planting the bomb that destroyed Mountbatten’s boat. A near-legend in the IRA, he is a leader of the IRA’s notorious South Armagh Brigade, which kills more than 100 British soldiers. He is one of the first IRA members to be sent to Libya to train with detonators and timing devices and is an expert in explosives. Authorities believe the Mountbatten assassination is the work of many people, but McMahon is the only individual convicted. Sentenced to life in prison, he is released in 1998 along with other IRA and Unionist terrorists under a controversial provision of the Good Friday Agreement.

(From: This Day In History: Mountbatten killed by IRA, by the editors of History.com, July 21, 2010, http://www.history.com)