- "Nine years Syrio Forel was First Sword to the Sealord of Braavos."
- ―Syrio Forel
The Sealord is a non-hereditary, elected position. Once elected, they serve for life.
In the books
In the A Song of Ice and Fire novels, the Sealord resides at the Sealord's Palace. Statues commemorating past Sealords and their achievements line the canals of Braavos.
The election process is described as somewhat chaotic. Moreover, given that the Sealord serves for a life term, when he dies it is said "knives will come out", until ultimately a new one is chosen. Inevitably, various power brokers and factions in the city often influence the elections to greater or lesser degrees, such as parties within the Iron Bank of Braavos, other wealthy merchants in the city, and old prominent families.
This is in contrast with the Triarchs of Volantis, who are elected for one year terms in what are described as fairly orderly elections. Of course, only members of the freeborn aristocracy are allowed to vote in Volantis, and there are five slaves to each free man in that city - their elections are understandably more orderly given that fewer people and opposing factions within the city can even participate in them.
It is unknown who the Sealord was that Syrio Forel served under for nine years. The current Sealord when Arya travels to Braavos (in the fourth novel) is Ferrego Antaryon - but it is unknown when Ferrego assumed office (if he was also Sealord during the events of the first novel). By the fifth novel Ferrego's health is said to be failing, and many in Braavos are anticipating the election for a new Sealord which will occur upon his death.
The position of Sealord is similar to the real-life position of Doge, a localized form of elected duke found in the Republics of Genoa and Venice. Braavos was inspired by real-life mercantile republics like Genoa and the famous Venice.
The Arsenal · Titan of Braavos · House of Black and White · Isle of the Gods · Long Canal · Moon Pool · Palace of Justice · Sealord's Palace · Temple of the Lord of Light (Braavos) · Temple of the Moonsingers