How old are wheelbarrows?

The Inventors section of About.com says this:

History of Engineering: Wheelbarrow

Chuko Liang (181-234 A.D.) of China is considered to be the inventor of the wheelbarrow. Liang was a general who used the wheelbarrows to transport supplies injured soldiers. The Chinese wheelbarrows had two wheels and required two men to propel and steer.

I say that a two-wheeled "wheelbarrow" is just a handcart, and not nearly as elegant as a one-wheeled conveyance.

And seriously? Were there no wheelbarrows in the world before the third century? I doubt that very much, but if it's right, let's have it. Anyone who knows or cares anything about wheelbarrows, or just thinks they're great, or maybe has once considered them kind of cute—send links or photos or comments.

Wheelbarrows at Lowe's Home Improvement Store near my house, 2012