The Last Legion (2007)

It’s not specifically marketed at children, but this action-adventure romp directed by Doug Lefler is certainly well-suited to the younger viewer. 

Thomas Sangster plays Romulus Augustulus, who is descended from the Caesar bloodline when his parents are killed. He is taken in by the kindly Aurelianus Ambrosius (Colin Firth) and Mira (Aishwarya Rai), and guided by the wise – and oddly bearded – Ambrosinus (Ben Kingsley). 

It’s quite entertaining in a fairly silly manner. The only real criticism is that Sangster could’ve been more of a hero, instead of someone that things merely happen to. That way, you might have found yourself actually rooting for him.