I think I'm beginning to detect a western bias.

Ever since I first played the video game, "Romance of the Three Kingdoms," I have been interested in that era of Chinese history. I think you guys are underestimating their technology, their leadership, and (most importantly) their sheer numbers. The question seems to ask if Rome could have conquered China. I don't think China could have marched westward and taken Southern Europe. But, I definitely think they would hold their ground and successfully repel a Roman invasion. China definitely deserves more than my single vote.

PS: I would love to see a few more Eastern leaders in your "Best commander of ______ era?" threads.