For how long was England a republic after Charles I was executed?
11 years
Britain was a republic from the execution of Charles I in 1649 until the Restoration in 1660: 11 years.
Correct answer
12 years
12 years would extend the republic to 1661, but Charles II was restored to the throne in 1660.
10 years
10 years would only reach 1659, one year before Parliament invited Charles II back.
9 years
9 years would end in 1658, the year Cromwell died; the republic lasted until 1660.
Explanation
England became a republic, called the Commonwealth, after Charles I was executed in 1649. Charles II was invited back in 1660, after 11 years as a republic.