How did a family of Tudor sheep farmers from Northamptonshire reach the upper aristocracy by the Restoration, and how did they continue to consolidate their position at the apex of society through the 18th and the 19th centuries?

The Spencers, like the Windsors, are a dynasty, and one of the most successful families that England has produced. But how did a family of Tudor sheep farmers from Northamptonshire reach the ranks of the upper aristocracy by the time of the Restoration, and how did they then continue to consolidate their great position at the apex of society through the eighteenth and the nineteenth centuries? The Spencers have quietly adapted from one generation to the next, sweeping up heiresses and magnificent estates, buying great libraries and pictures, then building London's most beautiful palladian mansion to house them. Family characteristics emerge, as do family traditions and attitudes to life. And, by the zenith of the eighteenth century, almost everyone who is anyone in politics seems to be related to this overwhelming family.