I've been researching Wudang and Daoist thought of late and I came across a story of famous Wudang monk who wore a shirt of armor underneath his robes and it got me thinking, I've seen vamp-braces or forearm armor depicted in Chinese martial arts over the years but did the Shaolin Monks use or wear armor of any kind? At some point they did serve as Imperial body guards.

I know there is a practice of body hardening, various "Iron Vest/shirt", Gene's favorite "Iron Sphinctor" etc...

Does anyone know what types of armor they may have used?

If they didn't wear it, how did they fair in pitched battles against armored soldiers? Why wouldn't they wear it? Is it against their vows as a Monk?