in 1584, Mary proposed an "association" with her son, James: she was ready to stay in England, abandoning her pretensions to the English Crown. For Scotland, she proposed a general amnesty, agreed that James should marry with Elizabeth's knowledge, and agreed that there should be no change in religion. Her only condition was the immediate alleviation of the conditions of her captivity.
James went along with the idea for a while but then rejected it and signed an alliance treaty with Elizabeth, abandoning his mother. Elizabeth also rejected the association, because she did not trust Mary to cease plotting against her during the negotiations.
After eighteen and a half years in custody, Mary was found guilty of plotting to assassinate Elizabeth in 1586, and was beheaded the following year at Fotheringhay Castle.
her last words were, In manus tuas, Domine, commendo spiritum meum ("Into thy hands, O Lord, I commend my spirit")
Mary's request to be buried in France was refused by Elizabeth; her body was exhumed in 1612, when her son, King James VI and I, ordered to reinter it in Westminster Abbey in a chapel opposite the tomb of Elizabeth