The Duke of Portland became Prime minister on two separate occasions spread out over two decades apart. In the first administration, his government was heavily concerned with the power of the East India Company, particulary with regards to Warren Hastings. In 1783 Charles Fox attempted to persuade Parliament to pass a bill that would replace the company's directors with a board of commissioners. King George III was hostile to the vote but wanted all those who voted for it to be classified as an enemy. This was an obvious attempt to railroad the power of Parliament and led to the Duke's resignation forthwith.
The French Revolution of the 1790s was a challenge to conservative Whigs and led to the Duke breaking with Charles Fox and the more liberal wing of the Whigs. This meant that the Duke of Portland could sit in the government of Pitt the Younger and indeed would be an acceptable compromise candidate after Pitt's death. By now too old and ill to run the government, he mostly left his Cabinet to do what they wanted. The period was marked by rivalry between two of his most powerful ministers, Castlereagh and Canning. Indeed, this rivalry culminated in a duel between the two in 1809 over the running of the Peninsular War. Portland resigned shortly afterwards, citing ill-health. In fact, he died just weeks later.