Queen Elizabeth II, already the oldest monarch in British history, reached another milestone Wednesday when hers became the monarchy\'s second-longest reign. There was no official commemoration of the event, The Daily Telegraph reported. At 59 years, 110 days, the queen passed her remote ancestor, George III. Elizabeth, who turned 85 last month, will beat her great-great-grandmother Queen Victoria\'s record if she lives another four years and a bit. Victoria, who had just turned 18 when she became queen in 1837, reigned for 63 years, seven months. The only current head of state who has been around longer is King Bhumibol Adulyadej of Thailand. He was six years into his reign when Elizabeth became queen. The queen, who attends almost 500 official events a year, spent the day unofficially at Windsor Castle. She was on hand when her horse, St. James, won two events at the Royal Windsor Horse Show, the Daily Mirror said. Buckingham Palace released a photo, taken at Easter, showing the queen and her two youngest grandchildren riding in Windsor Great Park. In 1952, when Elizabeth became queen, Winston Churchill was prime minister, and the country was still struggling to recover from World War II. She has reigned through 11 more prime ministers and six archbishops of Canterbury.