After the Siege of Candia, Grand Master Cotoner feared that the Ottomans would turn their gaze to Malta to avenge themselves against the Knights for helping the Venetians during the fighting.

Action was taken immediately and the Cottonera Lines project began under the direction of military engineer, Count Valperga. On 28 August 1670, the Grand Master laid the first stone that was to be part of the bastion of St Nicholas.