Until 1911, prime ministers had to guide legislation through the Commons and the Lords and obtain majority approval in both houses for it to become law. This was not always easy, because political differences often separated the chambers. Representing the landed aristocracy, lords temporal were generally Tory (later Conservative) who wanted to maintain the status quo and resisted progressive measures such as extending the franchise. The party affiliation of members of the Commons was less predictable. During the 18th century its makeup varied because the Lords had considerable control over elections: sometimes Whigs dominated it, sometimes Tories. After the passage of the Great Reform Bill in 1832, the Commons gradually became more progressive, a tendency that increased with the passage of each subsequent expansion of the franchise.