Elizabeth I, daughter of Henry VIII, is the only English queen never to have married. The iconic Tudor monarch's last visit to Kenilworth 450 years ago may hold some clues to her solo reign – as revealed in a new art installation at the castle, depicting betrayal, beheadings and an elaborate declaration of love. On a July evening in 1575, 41-year-old Queen Elizabeth I arrived at Kenilworth Castle in Warwickshire, UK, for what would be her longest and last visit. She had given the castle to Robert Dudley in 1563 and granted him the title of Earl of Leicester the following year. Dudley was a great favourite of the Queen and is thought to have been her childhood friend. The precise nature of their close relationship was the subject of much gossip. Prior to the unmarried Queen's arrival, Dudley had given the magnificent castle a major refurb. New buildings had gone up, a new garden had been created and the estate had been landscaped. And the earl pulled out all the stops to lay on extraordinary entertainment in the form of music, dancing, acrobatics, spectacular fireworks and dramatic interludes performed by costumed actors. On the huge mere surrounding the castle, there was a moving island inhabited by the "Lady of the Lake". There was a 24ft (7.3m) dolphin that concealed musicians, and an 18ft-(5.5m) long swimming mermaid. No expense was spared. It cost Dudley £1,000 ($1,400) a day – millions in today's money, and the whole extravaganza has been interpreted as an elaborate and expensive courtship display; the 16th-Century ruling class's equivalent of hiring a plane to fly a "Marry Me" banner. "The 1575 festivities were an attempt to woo Elizabeth – marriage is a theme in some of the events," Jeremy Ashbee, head curator of properties at English Heritage, tells the BBC. "Dr Elizabeth Goldring, who has made a detailed study of Lord Leicester, has called it 'his last throw of the dice'."