Why was the act of settlement passed?

It was passed in 1701 to resolve the issue of succession to the English and Irish thrones of the Electress Sophia of Hanover and her successors who are non-Catholics. This act was pressed by the inability of King Wiliam III and Queen Mary II as well as Queen Anne who was Mary’s sister to give birth to an heir.  Sophia’s line was Protestant her son became King George I and started the Hanoverian Dynasty. This happened after the death of Queen Anne in August 1714.  The act played an important role in the establishment of a King of Great Britain, England and Scotland that now had a shared ruler since 1603 but continued as individual governing countries.