Ordered to be built by D. Pedro I in the second quarter of the 14th century, with the intention of collecting tributes/taxes owed by the Jews and Moors on St. Martin's Day. This building with Manueline characteristics separated the old town of Pombal, to the east, towards the Castle, from the new town, to the west, towards the Arunca river, serving as a border to what was inside and outside the town's walls.
In 1509, during the reign of D. Manuel I, it underwent structural improvements, and he ordered the installation of a mechanical clock and a bell, so that the ringing of the Trindades would always sound at the right time. Around 1776, the Marquis of Pombal had this bell transferred to the Prison building.
In 2014 it underwent improvement works, with the aim of welcoming its visitors by making its history known.