The raid on the River Medway and Upnor Castle

In June 1667, a fleet of ships sailed down the river Medway and attempted to attack Chatham docks. They did not quite get as far as they would have liked but the damaged they caused was enough to cause embarrassment in the English Court of King Charles II, especially as his own flagship was taken and a fort – Upnor Castle was built to protect the docks and had failed in its one task. The attacking fleet was the Dutch and it was during the time of the second Dutch War between England and the Netherlands.

In the 1660’s the English navy was not as great as it had once been. Due to lack of wars, it had lapses in development to the point where we were actually using Dutch ships to trade in the seas around our Island, as they were the most up to date ships in Europe. However, this soon changed when the navigation Act was passed in 1651 making law that all goods bound for England had to be carried by an English made ship. This act made the relationship with the Dutch sour and would eventually lead to the first Dutch war.

In 1665 the second war with the Dutch would start, this time the English being responsible when they attacked a large Dutch merchant fleet and then landing at the nearby town of West-Terschelling and ransacking it to the ground. Of course, the Dutch were fuming at this and decided that it would not go unavenged.

A man named Johan De Witt had decided that the peace talks with Charles were pointless and wanted a victory and pay back against the English. His plan was to cross the North Sea with 62 ships, 15 small vessel and 12 fire ships and attack the English on their own soil. They set off for the Medway at the start of June.

During the time that the English knew the Dutch were on their way no real defence were put into places, we seemed to have sat ideal not really thinking that they were a threat, especially somewhere as far inland as Chatham was. Only three guard ships and three fire ships were left at the docks, thinking it would be enough.

by Pieter Cornelisz van Soest, painted c. 1667

On 6th June, the Dutch fleet reached Canvey Island and Sheerness. Not much plundering was done due to orders being given that they were not to stop to the British level and do what they did at West-Terschelling a few years previous. From these two islands at the mouth, the Dutch fleet continued inwards. By this time, Charles had ordered his militia to mobiles in addition to sending Admiral George Monck to Chatham to check on their situation – and it was dire with only 12 of the 800 men at the dockyard and no weapons. He acted as quickly as he could but only time would tell if it was to be enough. Meanwhile the Dutch continued to sail up the Medway breaking through a defensive chain at Sheerness. They also attacked any unmanned ships and set them alight, making them useless to all. In addition, the British had already sunk a number block ships to hinder the Dutch trying to get down the river and a number of other ships to stop the Dutch capturing them.

View from Upnor Castle of Chatham Docks. Phot0 Credit Laura Adkins

After much destruction, the Dutch withdrew back down the Medway on 14th June with the HMS Unity and the Royal Charles with them. Jeroen van der Vliet, a curator at the Rijksmuseum states that ‘It was one of the last times England was invaded by an enemy force while in the Netherlands it is regarded as the “high water mark of Dutch naval power.”

So why were the Brits so unprepared? If they had such a large fleet in the Medway, why were there not more defences to prevent such an attack? Well along with the fact that, even though there were spies in Europe who had pre warned them of a potential attack the authorities did not believe that one would actually be launched. In addition, there were such defence in place. The biggest defence was Upnor Castle just further down the river to Chatham Docks. 

Photo Credit Laura Adkins

Until the time of Upnors creation, a small number of defences around the River Medway but none were seen as being able to provide sufficient defence and protection of the fleet at Chatham docks. There was Rochester Castle, which although impressive was unable to actually provide, and protection to the ships anchored nearby. Then there was Queensbourgh Castle further downstream but was not lager enough to protect the Medway itself, only ships planning to attack Sheppey. There was a small blockhouse at Sheerness, which had become obsolete since its creation. The decision was taken to build a new large defensive building on the bend in the River Medway and this was to become Upnor Castle.

Photo Credit Laura Adkins

Upnor was built in 1559-67 and designed by Sir Richard Lee, a military engineer. However due to him being occupied the actual build of the site was overseen by his assistant Humphrey Locke. It was a quite design in so that it was a solitary bastion parcelled only by Milton blockhouse Gravesend which was built in 1539. It had an angled bastion, which enable the guns to cover the river approached both down and upstream. Behind the bastion was a two storey building which could hold further guns and was where the accommodation rooms were based along with the magazines.

Photo Credit Laura Adkins

In 1596, Lord of Effingham the lord Admiral would visit Upnor and stated that it had to either be properly manned or destroyed to prevent it falling into enemy hands. It seemed that the fort had been an out of sight, out of mind site. Improvements were therefore made between 1599-1601. The bastion was modified so it could take the weight of heavier weaponry. A wooden palisade was created at the front of the castle to defend against land attack. In addition a gatehouse and curtain wall were added which can still be seen today, along with two new towers, the North and South.

In 1653, a fire broke out at the Castle damaging much of the gatehouse. Some evidence of the fire can be seen today. Repairs were made in brick, which gives it s distinctive look, which can be seen by visitors to Upnor today. During the attack by the Dutch in the Medway Upnor did try her hardest to prevent the ships from travelling towards the docks. Additional troops had been sent to the area and to man Middleton Battery, which had been hastily erected in one night opposite Upnor. However, both Upnor and Middleton Battery were not enough.

“I do not see that Upnor Castle hath received any hurt by them though they played long against it; and they themselves shot till they had hardly a gun left upon the carriages, so badly provided they were.” – Samuel Pepys

It was decided that such a humiliating attack cannot happen again and so changes were made to the defence of the Medway. A new bastion, Garrison Fort was built near Sheerness, alone with another two outposts Cockham Wood Fort and Gillingham Fort further down the Medway. More were built as time went on resulting in Upnor Castle itself becoming redundant. However, it was not useless. It was deicide that Upnor would become a powder magazine. The roof-level gun platforms were removed and the building itself heightened to give it more internal space. A water jetty was also added to the bastion so the powder boats could get alongside.

A survey carried out in 1691 recorded that it held 5,206 barrels of powder, 164 iron guns, 62 standing carriages, 100 ships carriages, 7125 round shot with more than 200 muskets and 77 pikes.

By 1827, Upnor was used as a magazine and was part of the Naval Armament Supply Department until the late 19th century. In 1945 it became a museum, open to the public and the management was taken over by English Heritage in 1961. Today it is a grade I listed building and Medway Council manages events.


Coad, J (2017) Upnor Castle. English Heritage; London

Anon (nd) Upnor Castle. Available from:[Accessed 06/04/19]

Gupta, T (2017) Battle of Medway: The English defeat that’s largely forgotten Available from: [Accessed 24/3/2019]

Syeda, S (2017) The Royal Navy’s Darkest Day: Medway 1667 Available from: [Accessed 24/3/19]

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