Coat of arms of the Conti di Segni family. Gules, an eagle chequy sable and or. Note that this shows the reconstructed 13th-century coat of arms. From the 14th century, the eagle was usually shown crowned or  (cf. here, also attributed retroactively to the  13th-century popes,  cf. here)
File:C o a Innocenzo III.svg
User:Odejea, "eagle displayed" design by fr:Utilisateur:Rinaldum