There are many adaptations and versions to the tale of King Arthur and his Knights of the Round Table, with Merlin the sorcerer, and of the magical sword Excalibur, some versions which set it into stone, while others, handed out by a lady in the water. The Last Legion is essentially touting a story about the beginnings of Excalibur and how it took to the former. However, it took a long route to tell this story, going all the way back to 400-something AD, a time where Rome is in turmoil.
Actually Rome is in turmoil ever since Julius Caesar got killed by friends, Romans, countrymen. In a time where generals scheme to usurp the throne and politicians of the Senate are corrupt as hell, it's little wonder why one of the best and most loyal generals Aurelius (Colin Firth) gets recalled to protect the rear of the new boy-king-god-Caesar Romulus Augustus, played by Thomas Sangster (the kid in Nanny McPhee and Tristan+Isolde). Naturally the enemies spring a surprise attack, and our merry men have to flee Rome, and journey to Britain to regroup with the 9th Legion (henceforth also known as the Last Legion), bringing in tow a seer Ambrosinus (Ben Kingsley), and a lady warrior in Mira (Aishwarya Rai).
Like most medieval stories with elements of magic or involving the higher powers from Mount Olympus, The Last Legion does away with the sorcery portion, like what Troy and King Arthur had done, opting instead to focus more on reality, and what possibly could have been done without divine intervention, or fantastical assistance. Thus this makes Kingsley's role a little redundant, and relegates him into a fortune teller rather than an all powerful wizard, despite his garb looking a lot like Gandalf's.
While it could have gotten away with its material given 10 years back, unfortunately the stakes in the genre have been raised, and everyone's expecting a spectacle of huge armies battling in hand to hand combat, with its combatants having some form of fancy killing moves. The Last Legion pales in terms of providing that level of detail and spectacle, and chose instead to provide unsophisticated battle scenes, or swordplay that is a tad too uninspiring. Most of the fanciful moves were reserved for Aishwarya, but even that too began to become repetitive. Not even her booby trapped enhanced short sword offered anything we're never seen before.
With characters you don't really care about, what made it a little unbearable amongst the good guys, was the totally hokey, unbelievable romance between Rai and Firth's characters. It doesn't mean that having characters from the opposite sex means they find each other irresistable and want to get into each other's pants. There is absolutely zero chemistry and zero buildup. One minute they're allies, the next they're admiring each other's swordplay, and then, the bed beckons. And if the villains justify what kind of heroes we get, then it's a no brainer that they are bland and devoid of any interesting notion. World domination seems to be their only objective, and both the Romans and the British (using the term loosely here) villains are merely caricatures.
As I said, while The Last Legion might have worked if it's released 10 years ago, this movie can't justify it being made now. It's suitable at most for that DVD rental for a lazy afternoon, but nothing more, and only if you're in dire need of some, or any, form of entertainment.