Cromwell is a 1970 film, based on the life of Oliver Cromwell who led the Parliamentary forces during the English Civil War and, as Lord Protector, ruled Great Britain and Ireland in the mid-17th century. It features an all-star cast led by Richard Harris as Cromwell and Alec Guinness as King Charles I. There is also Robert Morley as Edward Montagu, 2nd Earl of Manchester and Timothy Dalton as Prince Rupert of the Rhine.
Oliver Cromwell is a devout, God-fearing, landowner and former politician. Disgusted with the policies of King Charles I, he plans to take his family to the New World, but, on the eve of their departure, he is drawn into the tangled web of politics and religion that will result in the English Civil War.
Charles needs money in order to fight wars against the Scots and the Irish. The Parliament of England will not grant him his requests unless he agrees to reforms that could lead to a constitutional monarchy. Committed to the Divine Right of Kings, Charles refuses. When he attempts to arrest five members of Parliament (in reality Cromwell was not one of them), war breaks out in England itself, Parliament against the King, both sides convinced that God is on their side.
When the Parliamentary forces in which he is an officer prove ineffective, Cromwell sets up the New Model Army and soon turns the tide against the King. Charles goes so far as to call on help from Catholic nations, which disgusts his Protestant supporters. He is finally defeated but, a brave man in his own way, he still refuses to give in to the demands of Cromwell and his associates for a system of government in which Parliament will have as much say in the running of the country as the King.
Cromwell later hears from Sir Edward Hyde, the King's once-loyal advisor, that Charles has secretly been raising a Catholic army to resume the war against Parliament. He and his supporters thus have Charles put on trial for treason. He is found guilty and sentenced to death. Charles bravely faces execution and even his most ardent critics are moved by his dignity. There is little celebration or satisfaction in his death, even from Cromwell.
However, Parliament soon proves itself just as useless in governing the country and, like the late King, Cromwell is forced to undertake a coup. But where Charles had failed, Cromwell succeeds and takes over in order to bring in more stable government.
After Cromwell's death, Charles I's son, Charles II, returns to become King of an England "never to be the same again".
Alec Guinness as King Charles I - Execution Scene