Beat the Brits!

So I'm playing a Conqueror's game with my friend. It was a 1v1v1v1 death match but it's just two of us now. He's the Brits and I'm playing as the Byzantines. A naval we had two naval battles which ended up tying. So now we've decided on an area for a final land battle. He's got an army of 117 made mostly of Longbowmen, Arablests, Cavaliers and Light Cavalry. My army is 173 is mostly Cataphracts and Camels supplied by Head Cannoneers. He's got a few onagers and trebuchets and I got a few as well. Any ideas on how to beat him? He's convinced he's got me beat