Final answer:
In 1568, Elizabeth I put her cousin Mary, Queen of Scots, under house arrest.
Step-by-step explanation:
In 1568, Elizabeth I had her cousin Mary, Queen of Scots put under house arrest. Mary, Queen of Scots was a possible claimant to the throne of England and posed a threat to Elizabeth's rule. Elizabeth suspected that Mary was plotting against her and saw her as a rival to the throne.