1964 election and his retirement from the House of Commons, he had been Father of the House. There was little consultation of Trinity fellows prior to Butler's appointment, but his opponents had backed down in the face of public approval. Butler was the first master in 250 years who had not been himself educated at the college. Charles, Prince of Wales, studied at Trinity (1967–1970) during Butler's time as Master. Initially it was thought that he might study an ad hoc course; a humorous cartoon showed Butler telling the Prince that he was to study a specially made-up history course "in which I become Prime Minister". Instead Butler recommended that unlike previous members of the Royal Family, Prince Charles live in College, study for a normal degree and sit Finals like any other undergraduate. After initial reluctance, the Palace agreed. Butler was publicly promoted as a mentor and counsellor to the Prince by making himself available for a 45-minute time slot each evening before dinner if the Prince wished to seek his advice. He turned a blind eye to Prince Charles keeping a car in college (in breach of the rules) but exclaimed "Hell no!" when the Prince asked if he might join the Labour Club. Butler also gave Lucia Santa Cruz, his research assistant for his memoirs, a key to the Master's Lodge and often let her stay, which gave rise to rumours that he was facilitating a romance between her and the Prince. Butler's appointment to the Order of the Garter on 23 April 1971 was seen as a gesture of recognition for his guidance of the young Prince. Butler soon earned respect by his brisk chairing of College Council Meetings, which was important because of Trinity College's huge investments in land and businesses, which generated an income of £1 million per annum at the time. He was also a director of Courtaulds, the family company, at this time. By 1971, the fellows had warmed to him enough to vote recommending (successfully) that he be given a second six-year term, despite the normal retirement age for masters being seventy. Butler's memoirs, The Art of the Possible, appeared in 1971. He wrote that he had decided to "eschew the current autobiographical fashion for multi-volume histories". (Macmillan was bringing out an autobiography, which would eventually run to six large volumes.) The work, largely ghosted by Peter Goldman, was described as