The first sign of the Masquerade was around 1343 DR. They had infiltrated many governments and several other mercenary companies in preparation for potential future jobs. In truth, the Masquerade were the secret army of the Unseen, ready to be used at the right time.
They usually worked undercover to infiltrate the target. The Masquerade also used a large number of informants. The true Masquerade members had mental blocks implanted by a high-level psionicist. They usually only spied on or assassinated targets. The only kind mission in open battle that they accepted was to break sieges.