Can you tell how many years Mary, Queen of Scots, was imprisoned?

Mary, Queen of Scots, had a pretty turbulent life, and a significant chunk of it was spent in captivity. To understand why she was imprisoned, we need a bit of background. Mary was a Catholic claimant to the English throne, and in the 16th century, this made her a threat to Queen Elizabeth I, who was Protestant. After being forced to abdicate the Scottish throne, Mary fled to England seeking protection from her cousin, Elizabeth. However, Elizabeth saw Mary as a potential rallying point for Catholic rebels. So, rather than offering sanctuary, Elizabeth had Mary imprisoned. This imprisonment lasted for about 20 years, from 1567 to 1587. During this time, she was moved between various castles and manor houses in England. Eventually, Elizabeth's advisors convinced her that Mary was involved in plots to overthrow her, leading to Mary's execution in 1587. While 11 years, 30 years, and 4 years might sound plausible, the historical record clearly shows that Mary was imprisoned for approximately two decades before her execution.