Was Mary Stuart A Success Or A Failure

Born prematurely to James V of Scotland and Marie de Guise of France, Mary Stuart was the only legitimate child to survive to adulthood. Six days after birth, on December 14th 1542, Mary became Queen of Scotland when her father died. Although the exact cause is unknown, it is speculated that James died from the effects of a nervous collapse following the Battle of Solway Moss, but most likely it occurred from drinking contaminated water while fighting.
Mary was an infant when she inherited the throne, and according to Scottish law, a regent would rule until she became an adult. From the beginning, two claimed to be the rightful choice: Catholic Cardinal Beaton and the Protestant Earl of Arran, who was next in line to the throne. Beaton staked his claim on the late king's will; but his opponents dismissed it as a forgery. Arran, with the political support of his friends and relatives, became regent until 1554 when he was succeeded
On July 1, 1543, when Mary was six months old, the Treaty of Greenwich was signed by the Earl of Arran and Henry VIII. The treaty promised that at the age of ten Mary would marry Edward and move to England, where Henry could oversee her upbringing. The treaty also stated that the two countries would remain legally separate and that if the couple should fail to have children the temporary union would dissolve.
Shortly before Mary's coronation on September 9, 1543, however, Henry VIII arrested Scottish merchants headed for France and impounded their goods. The arrests infuriated those in Scotland, the Earl of Arran became Catholic and allied himself with Cardinal Beaton. A few months after Mary’s coronation, the Treaty of Greenwich was rejected by the Scottish Parliament. In May 1546, Cardinal Beaton was murdered by Protestant landowners, and fearful for her safety, Mary's guardians, turned to the French for