Portsmouth was a small port until Henry V decided to establish a British Navy in 1415. Portsmouth became the main harbour used by the navy and in the 1490s Henry VII fortified the sea walls and then built Britain first dry dock at Portsmouth. In 1540 Henry VIII expanded it into the first royal dockyard. The fortress at the mouth of the harbour was strengthened by Bernard de Gomme, Charles II's chief engineer. The bastions were lengthened to take 28 guns.
In 1823 John Rennie helped the economy of the city by the building a canal that enabled goods to be transported from Portsmouth to Chichester and London. Railway lines were built to Portsmouth from Chichester and Brighton but it was not until 1853 that the Portsmouth Railway Company got permission to build a direct line to London.
Portsmouth, the largest fortification, beyond comparison, that we have in England. The situation of this place is such, that it is chosen, as may well be said, for the best security to the navy above all the places in Britain; the entrance into the harbour is safe; but very narrow, guarded on both sides by terrible platforms of cannon. There is a brick platform built with two tire of guns, one over another, and which can fire in cover, that the gunners cannot be beaten from their guns, or their guns easily dismounted. The docks and yards are now like a town by themselves and are a kind of marine corporation, or a government of their own kind within themselves; there being particular large rows of dwellings, within the new works, for all the principal officers of the place. The tradesman likewise have houses here, and many of the labourers are allowed to live in the bounds as they get lodging.