In May 1570 Shrewsbury conducted her to Chatsworth, where he foiled another cabal for her release. Cecil and Mildmay visited Chatsworth in October, and agreed on Mary's removal to Sheffield Castle (Shrewsbury's principal seat), which took place shortly afterwards. At Sheffield, apart from occasional visits to the baths at Buxton, to Chatsworth, or to the old Hardwick Hall, she remained under Shrewsbury's guardianship for the next fourteen years. During the winter of 1571–72 the earl was in London, the queen during his absence being left in charge of Sir Ralph Sadler. Meanwhile, in 1571, Lord Shrewsbury was appointed Lord High Steward (the premier Great Office of State) for the trial of Thomas Howard, 4th Duke of Norfolk (regarding the Ridolfi plot). Finally, in 1572, Lord Shrewsbury was appointed Earl Marshal, a position that he held (along with the aforementioned position of Justice in Eyre) until his death in 1590.