Finding a new husband was a complicated affair for Mary. She had to consider whether her choice of husband would upset Protestants, Catholics, Scottish nobles and especially Elizabeth I. Elizabeth stated that she would name Mary as her heir if she married an Englishman. In 1565, Mary married her cousin Henry Stewart, Lord Darnley, on Elizabeth's advice.
Look at the family relationships linking Mary, Darnley and Elizabeth and the crowns of Scotland and England. Produce a spectrum of opinion noting how for or against the marriage different individuals or groups were at the time, supported by evidence.