Tattoos in Roman Military/Society

[Celtic505]

I was wondering about how my tattoos would make my Roman impression look rather innaccurate but it led me to wonder about the practice of tattooing in Roman society but particularly the Roman army. I honestly know nothing of the practice in Roman society but know tattoos have been around quite long before the Romans, the only exmaple of Roman tattoos I've heard of is Maximus' SPQR tattoo in Gladiator. But hollywood aside, is there anything out there that speaks of this practice among soldiers? Was it frowned upon, punishable, encouraged, seen as a mark of lower status or not even done at all? Anybody know of any ancient writings or references, or perhaps examples in art of the period?