"I want battles like nothing anyone has ever seen on screen," Jackson said. I want every soldier fighting for himself - you have to come up with something."
Special effects designer Richard Taylor says this led to the writing of a "massive" principal code for the battle to give more than 200,000 digitized soldiers and some 6,000 horses distinctiveness and individuality.
"So to create these individual agents, there was a code that was especially written and developed," Taylor says, adding that it was like being involved in a living work of science fiction.
"It was the fact that you could get a computer to think for itself, that you could get 200,000 agents within the computer to think for themselves.
"So each of these computerized soldiers is assessing the environment around them, drawing on a repertoire of military moves that have been taught them through motion capture - determining how they will combat the enemy, step over the terrain, deal with obstacles in front of them through their own intelligence - and there's 200,000 of them doing that."
Basically, all the necessary information for decision-making was fed into this network of computers without determining for them whether they would win or lose.
But this attempt to ensure that they acted spontaneously almost sabotaged the the battleground sequences.
"For the first two years, the biggest problem we had was soldiers fleeing the field of battle," Taylor said."