Ralph de Brito, who married Joane de Herdewycke, is shown as having the same parents as his spouse. Surely this cannot be right. The Feudal History of the County of Derby (see Internet Archive) indicates that Ralf de Brito (born around 1184), the son of Robert de Brito and Cecilia de Ferrars, married Joane de Herdwycke (born around 1188), the heiress of William de Herdwycke.