In the episode Two Journeys, we are first introduced to a young William who stands beside his mother with his two younger siblings Marcellus and Celsa. His father, in Old Norse introduces him and his family to their two older cousins Bjorn, Hvitserk, and the other Vikings before one of the nannies takes him and his siblings away, but not before a cheeky William pulls his tongue out at an amused Floki.
In the episode The Great Army, William is seen on a boat with the Franks who arrive to come and collect his father Rollo who has just arrived back from his journey from the Mediterranean Sea. Rollo picks up his son as they are carried back to the palace. As his parents talk, William and his younger siblings are taken away by the nanny.
- William in English means "Strong-willed Warrior."
- William is the Angliczed form of the Germanic name Willahelm.
- Later in life, William earned the nickname Longsword.
- In history "Poppa of Bayeux" was the real mother of William.
|Season four appearances|
|A Good Treason||Kill the Queen||Mercy||Yol||Promised|
|What Might Have Been||The Profit and the Loss||Portage||Death All 'Round||The Last Ship|
|The Outsider||The Vision||Two Journeys||In the Uncertain Hour Before the Morning||All His Angels|
|Crossings||The Great Army||Revenge||On the Eve||The Reckoning|