How and why did people try to assassinate Elizabeth?

Answer 1

Both religious and political - Elizabeth had set up an Anglican Church which was moderately protestant - her aim was to set up a church which would be acceptable to all Protestants. The problem was she was the head of the Church and by doing this excluded all Catholics. Elizabeth tried to enforce this with an Act of Uniformity in 1552 which enraged many Catholics because if they were not Anglican they would not be considered loyal subjects. This helped to give a reason for Spain to try and attack England with the Armada in 1558. Moreover, Mary Queen of the Scots was a possible Catholic heir and the French wanted her to dethrone Elizabeth in a coup.

Answer 2

because she was never married and was not well protected