When King Bhumibol Adulyadej returned to Thailand from his studies in Switzerland in 1951 with his wife, Queen Sirikit, and their first daughter, Princess Ubolratana Rajakanya, the princess mother remained in Lausanne. She returned only periodically between 1952 and 1963 in order to attend significant functions or events, such as the birth of her grandchildren, the illness and subsequent death of Queen Sri Savarindira, the Queen Grandmother, or the ordination of her son. For these visits, she would stay only one or two months at a time, and only stayed for extended periods when the occasion demanded. On the king's state visit to 14 European countries and the United States in 1960, she remained in Thailand for six months, acting as Regent of Thailand during the king's absence, just as she did during subsequent state visits overseas until 1967.