With the opening of a new jain in 1887, a new gateway was necessary for the changing of guard and access to the courts of justice. It is also known as Porta do Cárcere (Jail Gateway); it was the third gate to be cut open during the XIX century.
It is 4.32 metres wide, the keystone is 7.15 metres high and the total height of the wall at this point is 8.10 metres. This gateway replaced previous staircases and this conditioned its dimension. The stairs -probably dating back to Roman times- and the tower as well as an artillery standpoint ("Reduto Cristina") had to be pulled down.
Debris was used for the new project and the rest went to Porta de San Fernando where gutters were being built at the time, as well as some landfilling around Campo Castelo Square.
Through this gateway we can reach the staircases at Campo Castelo square.