Margaret was one of the daughters of William de Ferrers, 3rd Baron Ferrers of Groby.
She married Thomas de Beauchamp, 12th Earl of Warwick, old enough to be her father.
They had one child, Richard, 13th Earl.
We've got 6 children. I've left notes on the other 5 suggesting what to do with them.
Other Margaret de Ferrerses are available.