This bastion was constructed upon the Spanish Baluarte de San Pedro [St. Peter’s Bastion], originally forming the eastern flanking position for the ditch, bridge and gate (Landport Gate), together with what would later become the Grand Battery. It was rebuilt in 1730 and named after Prince George of Hesse-Darmstadt, who commanded the Marines during the capture of Gibraltar in August 1704; by 1762 the battery mounted two 18-drs and four 4-pdrs.

Luis Bravo Landport defences 1627. San Pedro's platform is shown as L on the map.

Old drawing showing the Puerta de España gateway at the top and parts of both Villa Vieja and La Barcina on the right (1627 - Luis Bravo). The gateway is protected by the Bastion of San Pedro on the right.

Thomas James, in his book ‘The History of the Herculean Straits’, published in 1771, referred to the area of Hesse’s Demi-Bastion as follows:

‘The curtain (Grand Battery) has sixteen embrasures all mounted with a tapia parapet of twenty-two feet thick: the demi-bastion (called the prince of Hesse’s battery) has the parapet made in the same manner as the curtain, with two embrasures mounted on the face, two in the flank, and three in the rising part of the curtain; but, by reason of a great rock that projects in the inward line of the curtain, the parapet is not so wide: the rampart and the parapet is higher than the lower part of this curtain, which you ascend by eight steps.

‘This whole work was rebuilt in one thousand seven hundred and thirty, by lowering part of the battery eight feet, and raising a new parapet of tapia, with stone platforms and a new communication by eighty-four steps to a casemate in the king’s line: in front of the north bastion, curtain, Prince of Hesse’s Battery, and under part of the king’s Line is a covert way, the glacis of which is high enough to prevent the scarp wall from being seen below the cordon: under the glacis are galleries for mines with many chambers ready for service.’

1704 - Col D'Harcourt Northern Defences (cropped). Hesse's Demi-Bastion is shown as C.

1753 - Gabriel James Montressor Grand Battery (detail). Four embrasures can be seen within the demi-bastion; two facing outwards towards the landward approches and two covering the ditch.

In April 1811, the Lieutenant Governor, Sir Colin Campbell, instructed the Commanding Officer of the Royal Engineers, Sir Charles Holloway, to prepare a report containing their joint observations on the defence requirements for the Rock. This report, which included recommendations for the reinforcement of the area at the northern entrance to the City, was submitted to the Inspector-General of Fortifications, Major General Robert Morse. The Governor’s ambitious plans also involved the sloping northern face of Hesse’s Demi-Bastion which would be reformed into a horizontal wall with four embrasures cut into it. The interior of the demi-bastion, which was raw rock, would also have to be levelled. In the event, after due consideration, the proposals were found not to be feasible and the project of renovation was abandoned.

Plan Northern Defences 1796.

1859 Gibraltar fortifications map Northern Defences.

By 1885, all the guns mounted in this bastion were 32-pdrs. and, by the turn of the century, the bastion was considered to be of insignificant tactical and defensive purposes with a sanitary water pumping plant set up within the bastion in 1909.

Hesses Demi Bastion/1860s - Carl Goebel - Moorish Castle. Hesses's Demi-Bastion is clearly depicted in the painting as a covered casemated bastion with three embrasures.

Hesse's Demi Bastion with potruding piping works still clearly visible.