Also known as the Firenzuola Lines, they were built in the 17th and 18th centuries to protect the land front defences of the cities of Birgu and Senglea.

Later, a second line of defence was constructed, the Cottonera Lines, built around the Santa Margherita Lines. The city of Cospicua was founded in the 18th century within the Santa Margherita and Cottonera Lines. These lines were built to the designs of the Dominican Cardinal Fra Vincenzo Maculano da Firenzuola, hence the name Firenzuola Lines. The foundation stone was laid by Grand Master Lascaris on December 30 1638.