Final answer:
The two parts of the Protestant Interregnum in England are the Commonwealth (1649-1653) and the Protectorate (1653-1658), with the latter period under the rule of Lord Protector Oliver Cromwell.
Step-by-step explanation:
The two parts of the Protestant Interregnum are typically referred to as the Commonwealth and the Protectorate. The Commonwealth phase lasted from 1649 to 1653, following the execution of King Charles I and the establishment of a republic ruled by the Rump Parliament. The Protectorate began in 1653 when Oliver Cromwell, a militarily talented and devout Puritan, assumed the title of Lord Protector, establishing a form of military dictatorship until his death in 1658. His son Richard succeeded him but was ineffective, and by 1660, the monarchy was restored.