481
Context: https://en.wikipedia.org/wiki/Emperor_Gaozu_of_Han#Insurrection_against_the_Qin_dynasty
Liu was responsible for escorting a group of penal labourers to the construction site of Qin Shi Huang's mausoleum at Mount Li. During the journey, some prisoners escaped; under Qin law, allowing prisoners to escape was punishable by death. Rather than face punishment, Liu freed the remaining prisoners, some of whom willingly acknowledged him as their leader and joined him on the run from the law.
Enough to get a start, then he just kept stumbling into a series of opportunities to get more followers over and over. Also helped that the Qin dynasty was dealing with like 6 simultaneous rebellions from a previous war of expansion. Liu was in the right place at the right time and was such a massive improvement over the dickheads ruling most places under the Qin he just kept advancing.
Wonder if we could do something similar today?
Unfortunately, somebody already has...