During the 1981 Trooping the Colour ceremony and only six weeks before the wedding of Charles, Prince of Wales, and Lady Diana Spencer, six shots were fired at the Queen from close range as she rode down The Mall on her horse, Burmese. Police later discovered that the shots were blanks. The 17-year-old assailant, Marcus Sarjeant, was sentenced to five years in prison and released after three. The Queen's composure and skill in controlling her mount were widely praised. From April to September 1982, the Queen remained anxious but proud of her son, Prince Andrew, who was serving with British forces during the Falklands War. On 9 July, the Queen awoke in her bedroom at Buckingham Palace to find an intruder, Michael Fagan, in the room with her. Remaining calm and through two calls to the Palace police switchboard, she spoke to Fagan while he sat at the foot of her bed until assistance arrived seven minutes later. Though she hosted US President Ronald Reagan at Windsor Castle in 1982 and visited his Californian ranch in 1983, she was angered when his administration ordered the invasion of Grenada, one of her Caribbean realms, without informing her.

Answer this question, if possible (if impossible, reply "unanswerable"): What was Elizabeth's horses name in 1983?
unanswerable