History of Waterdeep - Age III, The Bloody Reign of the Guildmasters:

There was great turmoil in the City as the Guildmasters argued amongst themselves as to who should govern the City, and more than one merchant of power was found murdered. Groups of liveried bodyguards appeared openly armed on the streets, accompanying their masters, and two very troubled months passed as they bickered and parleyed (and occasionally dueled in the streets). At last, they decided that all Masters should rule Waterdeep together, in a council. The lesser nobles and many townsfolk protested, saying that the Lords ruled by right and by the people's consent. The Guildmasters, however, said that the Lords had not been seen since Ahghairon's death, and that they must have been golems or zombies, controlled by Ahghairon to conceal his lone rule -- and indeed, the Lords were silent and unseen, and continued to be so.

In truth, the Lords were real men and women whose identities had been compromised, over the years, by certain curious Guildmasters who had ordered them slain by their own closemouthed, loyal servants following Ahghairon's death. The only Lords still surviving (those who had remained secret) were Baeron, a woodworker, and Shilam, an apprentice wizard. These surviving Lords kept very quiet, and waited. The Guildmasters thought all the living Lords of the City had been eliminated, and took firm rule over Waterdeep.

The Guildmasters ruled Waterdeep for only six years ere their self-interested squabbling led to bloodshed. Open quarrels and a few murders quickly erupted into a brief but vicious series of street fights and midnight attacks. This strife, oftimes termed "the Guildwars" by sages (although it was never as long-drawn-out or so formal as to be called a "war" when it was taking place), left all but two Guildmasters dead, most of the City's best minds stilled, and much of the City's gold wasted or plundered with the Guilds in disarray.

The surviving Guildmasters were Lhorar Gildeggh of the Shipwrights and Ehlemm Zoar of the Gemcutters. These two - ruthless manipulators both - were well-matched and could not overcome each other, though their private armies clashed often in the streets. At length, they sickened of bloodshed, after many from both families were dead in the gutters, and agreed to rule together. Two thrones were set up in Castle Waterdeep, and from then the two argued bitterly over this and that, and the City was a place of tension and fear. All matters, including the recognition of new Guildmasters to rule the "headless" guilds, had to come before the Two Lords Magister, as Lhorar and Ehlemm were called. Few matters were settled.