Rendezvous with Yesterday - S1-E1
Character mistake: When Tony talks to captain of Titanic he states he was born in 1938, but in episode 4 "The Day the Sky Fell In" it is December 1941, he should be 3 years old, but as a young child he is about 12 years old.
The Revenge of Robin Hood - S1-E16
Character mistake: When Robin Hood and his gang ambushes the king's cavalry, one of his crack archers fumbles and drops an arrow as he is about to shoot.
