The Roman festival of Saturnalia, celebrated in mid-December, was a time of excess even by Roman standards, and a fascinating inversion of the typical social norms of the Roman empire. Dedicated to the god Saturn, the festival was marked by feasting and the giving of gifts, and a relaxation of the usually rigid hierarchies that defined Roman life. Slaves were allowed to don the clothing and accouterments of their owners, while their masters were expected to serve them, with their roles reversed for a single day at the culmination of the festival, on the evening of the 19th of December.

While most slaves sufficed with these fleeting privileges, others among them were given a tantalizing taste of power. The Roman Empire was highly legalistic and Saturnalia was no mere performance - during the 24-hour period, the masters were, for all legal intents and purposes, considered the property of their slaves. There are several accounts of fast-acting slaves using this precious time to concoct a more permanent reduction of stature for their former owners. Often they would ply their former owners with wine until they were helpless and compliant before ordering their guards to clad them in irons and drag them away for the process of eviratio (emasculation) or effeminatio (feminization).

The art of eunuch-making in the Roman empire at this time had reached a level of sophistication never before seen in human history and could be performed efficiently at short notice by a class of specialized surgeons. The former slave-owner would be immediately castrated, thereby permanently removing many of their former privileges and protections in a culture that revolved so much around authority and masculinity.

What followed would be a longer process of beautification that, on its completion, would leave the man perfectly feminized and, moreover, unrecognizable. They would be taught in the usual arts of love-making, how to dress and act subserviently. The former slave, now comfortably entrenched in his or her master's villa, would be wise to sell the ex-man on, should any of his allies attempt to exact revenge, or else have the 'slave's tongue removed, so that 'she' would be unable to call for help.

The Saturnalia power grab was of course an extremely risky grab at power. Most guards would never treat their employer thusly, even during Saturnalia, and so the slave would be wise to ensure they have leverage over the muscle of the household, either through a process of seduction or the promise of payment. Sometimes, this payment would take the form of their employer, once fully feminized.