Arms of William de Ferrers, Earl of Derby (1193 – 1254) and Margaret de Quincy (c. 1218 – 1280)
From p81 of Lacies Nobilitie by Sir John Ferne (1586)
Blazon: Per pale baron and femme argent six horseshoes sable and gules seven mascles conjoined 3, 3, and 1 or
I have previously discussed the disagreement over the Ferrers arms here. Ferne incorrectly refers to William as the Lord of Groby. The first Lord of Groby was William and Margaret’s grandson, also named William, who received the title in 1299 William and Margaret married in 1238 and had five children, including the heir to Derby, Robert. William previously had seven daughters with his first wife, the youngest of whom, Eleanor, later married Margaret’s father, Roger de Quincy.