Vicars is born on July 27, 1862 in Leamington Spa, Warwickshire, England, and is the youngest child of Colonel William Henry Vicars of the 61st Regiment of Foot and his wife Jane (nee Gun-Cunninghame). This is his mother’s second marriage, the first being to Pierce O’Mahony by whom she has two sons. He is very attached to his Irish half-brothers and spends much time at their residences. On completing his education at Magdalen College School, Oxford and Bromsgrove School he moves permanently to Ireland.
Vicars quickly develops an expertise in genealogical and heraldic matters and makes several attempts to be employed by the Irish heraldic administration of Ulster King of Arms, even offering to work for no pay. In 1891 he is one of the founder members of the County Kildare Archaeological Society and remains its honorary secretary until his death.
Vicars first attempts to find a post in the Office of Arms when in 1892 he applies unsuccessfully for the post of Athlone Pursuivant on the death of the incumbent, Bernard Louis Burke. In a letter dated October 2, 1892 his half-brother Pierce Mahony writes that Sir Bernard Burke, Ulster King of Arms, is dying and urges him to move at once. Burke dies in December 1892, and Vicars is appointed to the office by letters patent dated February 2, 1893. In 1896 he is knighted, in 1900 he is appointed Commander of the Royal Victorian Order (CVO) and in 1903 he is elevated to Knight Commander of the Order (KCVO). He is also a fellow of the Royal Society of Antiquaries of Ireland and a trustee of the National Library of Ireland.
In 1897 Vicars publishes An Index to the Prerogative Wills of Ireland 1536 -1810, a listing of all persons in wills proved in that period. This work becomes very valuable to genealogists after the destruction of the source material for the book in 1922 when the Public Record Office at the Four Courts is destroyed at the start of the Irish Civil War.
Vicars’ career is very distinguished until 1907 when it is hit by the scandal of the theft of the Irish Crown Jewels. As Registrar of the Order of St. Patrick, he has custody of the insignia of the order, also known as the “crown jewels.” They are found to be missing on July 6, and a Crown Jewel Commission is established in January 1908 to investigate the disappearance. Vicars and his barrister Tim Healy refuse to attend the commission’s hearings. The commission’s findings are published on January 25, 1908 and he is dismissed as Ulster five days later.
On November 23, 1912, the Daily Mail publishes serious false allegations against Vicars. The substance of the article is that Vicars had allowed a woman reported to be his mistress to obtain a copy of the key to the safe and that she had fled to Paris with the jewels. In July 1913 he successfully sues the paper for libel. The paper admits that the story is completely baseless and that the woman in question does not exist. He is awarded damages of £5,000.
Vicars leaves Dublin and moves to Kilmorna, near Listowel, County Kerry, the former seat of one of his half-brothers. He marries Gertrude Wright in Ballymore, County Westmeath on July 4, 1917. He continues to protest his innocence until his death, even including bitter references to the affair in his will.
In May 1920 up to a hundred armed men break into Kilmorna House and hold Vicars at gunpoint while they attempt to break into the house’s strongroom. On April 14, 1921, he is taken from Kilmorna House, which is set afire, and shot dead in front of his wife. According to the communiqué issued from Dublin Castle, thirty armed men took him from his bed and shot him, leaving a placard around his neck denouncing him as an informer. On April 27, as an official reprisal, four shops are destroyed by British Armed Forces in the town of Listowel. The proclamation given under Martial law and ordering their demolition states:
“For any outrage carried out in future against the lives or property of loyalist officials, reprisals will be taken against selected persons known to have rebel sympathies, although their implication has not been proved.”