After the execution of Charles I in 1649, the Scots declared his son king as Charles II. The English responded with an invasion led by Oliver Cromwell, resulting in defeats for the Scots at Dunbar and then at Worcester, opening the way for the English conquest of the country. Under the Tender of Union Scotland was declared part of a Commonwealth with England and Ireland in 1652, but despite repeated attempts, an act was not passed in Westminster to ratify the union until 1657. Under the terms of the union the Scots gained 30 members of parliament, but many posts were not filled, or fell to English agents of the government, and had very little say at Westminster. Initially the government was run by eight commissioners and adopted a policy of undermining the political power of the nobility i