 Mary returned to Loch Leven as a prisoner , from 17 June 1567 until her escape on 2 May 1568 . At the " battle " of Carberry Hill on 15 June , Mary surrendered to her noblemen , who opposed her marriage to the Earl of Bothwell . She was taken to Loch Leven and given into the custody of Sir William Douglas of Lochleven , spending most of her captivity living in the early 16th @-@ century Glassin Tower , at the south @-@ east corner of the castle . Aside from Sir William , the household included his mother Lady Margaret Douglas , mother of Mary 's half brother the Earl of Moray , and his brother George Douglas , as well as Willie Douglas , a young orphaned relative . Mary fell ill on arrival , and sometime before 24 July she miscarried twins that she had conceived with Bothwell . Only a few days later she was forced to abdicate as Queen of Scots , in favour of her infant son James . 
