In May 1662 King Charles II paid two visits to Portsmouth; the latter, on the 21st May went down in history as the day that the king married Catherine of Braganza at Government House and easily overshadowed the former, on the 18th May, when Charles met with his Chief Military Engineer Sir Bernard de Gomme to discuss progress on the refortification of Portsmouth. On this occasion de Gomme spent 17 days in Portsmouth and Gosport and was therefore present at the time of the marriage. It is not known if he was actually in attendance during the ceremony but as one of the most senior members of the King's entourage (he had been appointed Chief Engineer on 1st April 1661), it is possible.
Little is known of de Gomme's early life but the Act of Parliament that gave de Gomme citizenship in 1667 recorded that he was born in Torneus in Flanders, the son of Peter de Gomme, in 1620. His early years were spent in Flanders where he served a military apprenticeship in the armies of Prince Frederik Hendrik, the younger brother of Prince Maurits. He must have studied geometry and mathematics from an early age as by the time he was only 16 years old he was already working as a surveyor, possibly involved in the construction of the polders in Zeeland.
It is thought that about this time he first met Prince Rupert who was of a similar age and was to prove a lifelong patron. He was also learning from the English commanders who were fighting in support of the Dutch in the Low Countries, something of the English language and their military strategies. This made him an ideal member of Prince Rupert's staff, accompanying him when he travelled to England to fight in support of King Charles during the English Civil War. Several drawings made by de Gomme during the war have survived and these show he was adept at drawing battle plans and fortifications. He became the Royalists' Chief Engineer whilst still in his early twenties and such was his contribution to the King's cause that he was knighted in 1645.
Upon the surrender of King Charles at Oxford in 1646, Prince Rupert with de Gomme still at his side, was given safe conduct by the Parliamentarians to leave for the continent. De Gomme spent the next 14 years pursuing his career as military engineer during the wars with Spain. With the restoration of the monarchy in England in 1660, de Gomme returned to England to work as engineer in charge of all of the new king's castles and fortifications. Over the next 20 years de Gomme was involved in most of the major fortifications of the era, not all of them in England. Much of his early work was carried out at Dunkirk and Tangier, before turning his attention, under the king's instructions to Plymouth, Hull, Harwich, Sheerness and most notably at Tilbury. Impressive though many of these were, our concern here is for the fortifications of Portsmouth.
Although de Gomme had discussed the defence of Portsmouth with the king in May 1662 it wasn't until 1665 that extensive work was put in hand, this period of construction lasting five years until 1670. A second bout of work began in 1677 and again lasted five years. The result was one of the most fortified towns in the whole kingdom, rivalled only by Berwick.
When King Charles discussed the state of the defences around Portsmouth with de Gomme it was with the knowledge that they were not strong enough to withstand a determined attack. This is not to say they were in total disrepair since the Governor of Portsmouth in 1642, George Goring, had managed to hold back the Parliamentary forces during the Seige of Portsmouth and only surrendered when it became obvious that too many men had deserted to effectively mount a defence. One of the episodes during the seige that did not go unnoticed by de Gomme was the ease by which the Parliamentarians had been able to set up guns on the Gosport side of the harbour and lob missiles into the town. Plainly when considering the defence of Portsmouth he also had to think about protecting Gosport and this eventually widened to include the defences of the whole Solent as far west as Hurst and Calshot castles and including the Isle of Wight.
De Gomme began by surveying the existing fortifications which had not changed very much since the time of Queen Elizabeth. They consisted largely of mud banks with rounded bastions in the Italian style and a narrow wet ditch beyond. The resulting sketch is probably amongst the collection of 63 maps of Portsmouth made during this period (now in the British Library) and it shows the 16C defences with proposed modifications for Portsmouth in heavy black lines and the suggested enclosure of the Camber and fortifications at Gosport Point. The map below was amongst those made at this time.

Portsmouth and Gosport c1662 [BL Add MS16371 B]

With the set of maps completed and presented to the king, de Gomme headed back to Dunkirk and did not visit Portsmouth again until February 1665. This time, the circumstances were different; the Second Anglo-Dutch war was under way making it imperative that the work commence immediately. De Gomme would not be directly involved in construction work due to heavy commitments elsewhere, but he did stake out the new fortifications before leaving the ground work to seven commissioners under the Governor Sir William Berkeley and departing for Tangiers.
He returned to Portsmouth in late July 1665, having been provided with a pass by Samuel Pepys, this being a time of plague, and he stayed until September whereupon he departed for Plymouth to commence the construction of the Citadel there. The work at Portsmouth continued slowly for the next three years with de Gomme making only sporadic appearances, until September 7th 1668 when he was required to attend the King at Portsmouth. De Gomme produced further maps to show the King that the defences were close to their final form in this phase. There were now two moats, one within the other, with a glacis beyond the counterscarp; one ravelin stood before the Landport access into the town; there was as yet no bastion at Key (or Quay) Gate. The map also showed proposals for the development of defences at Southsea Castle and around the Dockyard.
A second phase of fortification began in late 1669, though there is no evidence that de Gomme was present on site until May 1670. Included in this work were the construction of bastions at Wimbletons, Pembroke, East and Town Mounts, the building of the Landport Gate and the provision of stone revetments to the flanks and bastions, topped by a stone cordon.

Portsmouth (South Side) December 1669 [BL Add MS16370 f.30]

Between 1670 and 1677 no major improvements were made to the fortifications, though some minor works to Government House and the Sally Port were mentioned. From 29th March to 10th April 1677 de Gomme was back in Portsmouth staking out his new works. These seem to have been refinements to his original plans but did cover new work around Spur Redoubt, the area north of Key Gate and north of the Landport Ravelin. Around this time de Gomme also produced plans for a set of barracks to be sited against the East Flank. Late that year a contract was signed with local contractor William Cozens who undertook to widen and deepen the ditch from Town Mount to Wimbleton's Mount. The ditch would now be 100 feet wide and seven feet deep.

Plan of the New Fortifications 1677 [BL Kings Top Coll xiv33]

1678 and 1679 saw further work aimed at completing de Gomme's design, though this was constantly being further refined as work progressed. In January 1679 the King, probably exasperated at the time being taken ordered de Gomme to Portsmouth to draw up a final statement of outstanding works. This showed that de Gomme was still revising his scheme even whilst the first guns were being mounted. If Charles thought this would be the end of the construction work he was to be disappointed as it dragged on a further five years. In the end, the King died before it was complete, leaving de Gomme to finish the work under King James II. On the 23rd November 1685 Sir Bernard de Gomme himself died and was buried in the chapel of the Tower of London, since when he has been largely forgotten.
The fortifications for Portsmouth, designed by Sir Bernard de Gomme, were typical of the age but the changing nature of warfare and ordnance moved on quickly after his death. Even at the time of construction the defences would have required an unfeasably large number of men to man them, coupled with this it was found that the complicated set of moats and barriers made it difficult for troops to communicate with each other and so co-ordinate any action. By 1730 an urgent need to remodel the defences was accepted and by good fortune a worthy successor to de Gomme was already at work. This was Colonel John Peter Desmaretz and it was he who between 1745 and 1756 redeveloped the defences and in so doing removed most of de Gomme's fortifications. Today the only parts that survived and can still be seen are at Long Curtain, part of King's (formerly Wimbleton's) Bastion, the remains of Spur Redoubt, the seaward side of 18 Gun Battery and the part of King James Gate in Burnaby Road.
"Fortress Builder" by Andrew Saunders
"A Military Heritage" by BH Patterson
"Fortifications in Old Portsmouth" by Arthur Corney