during the reign of Queen Maria II of Portugal, Seixal obtained the status of municipality. A few years later (1895), this status, was extinguished. At that time Amora was integrated into the municipality of Almada, while Arrentela, Aldeia de Paio Pires and Seixal was annexed into the municipality of Barreiro. Yet, three years later the municipality of Seixal was newly instituted.

As a consequence, by the 18th century, the municipality became