Following the expansion of Braavosi interests, growing disconsent led to riots against Braavosi presence in Lys.
In Lys, many, especially the disenfranchised lower classes, became angry at the increased power and influence of Braavos.
There were often incidents involving Bravos in Lys and the Magisters didn't react, which only helped to fan the flames.
This came to a head when a Braavosi was murdered by Varyo Velaryon. The local magistrate demanded an investigation and none of the noble houses resisted.
Varyo came to be beloved by the crowds for his handling of the situation in a martial way, and many of the underground Lyscene organised crime outfits came to idolise him as a leader against the Braavosi influence.
After a well-beloved Magister was killed, seemingly by Bravos, the rioting reached fever pitch with many Braavosi families being killed. The Magisters arranged to invite Varyo to be one of their number, but he had already set up a coup, declaring himself Prince of Lys.
The various gangs came under the banner of the 'Seahorses' after Varyo's sigil and came under the leadership of Caerys Embaregos who led them and other irregulars in aid of Varyo's troops, becoming somewhat of a company in Lys.
With Varyo on the throne the riots were eventually ended, and Varyo issued a proclamation imprisoning the Braavosi families as collateral against invasion.