Referenced by...: Crusader Kings II has an achievement for conquering England as William the Bastard titled "On English Neck a Norman Yoke". The game's cover image is also Wilfred of Ivanhoe himself, as "the device on his shield was a young oak-tree pulled up by the roots, with the Spanish word Desdichado, signifying Disinherited."
41 year old Robert Taylor as 25-year-old Wilfred of Ivanhoe. Naturally this also resulted in the 74-year-old Finlay Currie as 59-year-old Cedric the Saxon.
Outside of the father-son duo, we have 49 year old Harold Warrender as 34 year old Locksley, based on the fact that the Robin Hood of Richard's reign is traditionally identified with a (fictious) Robert Fitzooth, whose date of birth is said to be 1160.
On the brother side of things we have 47-year-old Norman Wooland as 37-year-old King Richard and 41-year-old Guy Rolfe as 28-year-old Prince John.
What Could Have Been: An early draft of the script would have had Ivanhoe and Rowena half-siblings and thus not love interests, Ivanhoe and Rebecca marrying in the end alongside with Rowena and a Norman nobleman in a Jewish ceremony. While good intentioned to show the ultimate peace between Saxon and Norman and Jew and Christian, it was considered controversial and thankfully resulted in Ivanhoe and Rowena remaining lovers in the final film but also begs the question who exactly the Norman Rowena would have married was? If it were De Bracy then that would result in some Unfortunate Implications with her falling in love with her kidnapper who attempted to force her into marrying him.
No Stunt Double: Roger Moore insisted on undertaking much of the stunt work himself, resulting in several injuries including three cracked ribs from a fight scene and being knocked unconscious when a battleaxe hit his helmeted skull. Moore later commented, "I felt a complete Charlie riding around in all that armour and damned stupid plumed helmet. I felt like a medieval fireman."
The 37-year-old Richard and 28-year-old John are played by a 47-year-old Julian Glover and 42-year-old Ronald Pickup respectively.
On the father-son side of things we have 34-year-old Anthony Andrews as 25-year-old Wilfred of Ivanhoe and 71-year-old Michael Hordern as 59-year-old Cedric the Saxon.
An inversion is 35-year-old Sam Neill as Brian de Bois-Guilbert, who is stated to be "past forty" in the book. Due to Sam being Older Than He Looks he looks even younger.
Unfortunate Implications with her falling in love with her kidnapper who attempted to force her into marrying him.