It's in the Signs: Walking Tour of Wisloujscie Fortress

Gdansk is one of my favorite cities. Rich in history, and constant examples of resilience make it a perfect place. Especially for “It’s in the Signs!”

In this example, we're taking a walking tour of Wisloujscie Fortress. (Read something like “wizz low eesha”, also known in Germany as Weichselmünde fortress.)

In ancient times, a large area around the south Baltic was the home of the Old Prussians. Wisłoujście is mentioned as early as the 800s (or so), with watchtowers recorded by the 1000s. In the 1200s, a band of crusader hospitaller knights, the Teutonic Order, came to subjugate the Old Prussians. The knights wanted control of, among other things, the ports and lucrative amber trade (plus, Christianize the population). As a result, they built many forts and castles around the area. For another example, to the south of Gdansk, there is the famous Malbrok (the largest castle in the world, by area).

Today, we go visit the site and roam it's bastions - join in, won't you?!

Closer to Gdansk, the Teutonic knights also established a wooden fort at the mouth of the Martwa Wisła river, controlling trade in and out of the port, and of course protecting their interests. They record building a watchtower in 1372, which was burnt down by a Hussite Sirotci raid against the knights in 1433.  

The knights re-built, but in brick this time – making a tower with defensive loopholes (firing slots for archers). However, its main purpose was to indicate a safe route into the Gdansk port. In short, it was a lighthouse – with a fire on its top. This makes the Wisłoujście fortress the oldest lighthouse  on the Polish coast. For example, the city, with its lighthouse is clearly marked as the burning tower on the Cara Mariana map of 1539 from the library in Uppsala, Sweden (see below!). 

Indeed, the Teutonic knights named a “Master of the River Mouth,” who controlled the travel along the waterway, plus maintained breakwaters, navigation signs and channel depth. From the 1400s ~ 1700s a “mooring pile” tax was collected in the Pile Chamber of the Main Town hall by the Pile Lords. Throughout, the port and region flourished. The image above shows the late 1600s fort (the triangles on the left), plus the long row of piles the Master maintained (on the right).  The image below is the fort with it’s wharfs, buildings and fairway (or farwater).

In the 1500s ~ 1600s, a complex of buildings were built on the site to serve the crews of merchant ships. For the ships, breakwaters, wharfs and mooring areas; for the men taverns and kitchens. This included a special pilots’ building where pilots could be hired to help captains through the farwater (or fairway, the mouth of the river into the port of Gdansk). Equally, in 1616 there were buildings for crews dedicated to rescuing shipwrecked sailors, as well as guards supervising the roadstead (i.e. the sheltered waters where ships can lie safely at anchor) around Wisłoujście.

The current lighthouse history stretches to the 1450s when the Polish king Kazimierz IV Jagiellon-czyk granted Gdansk privileges to control the sea trade, build fortifications and maintain an army. This also marked a blossoming of Polish-Lithuanian plus pan-European trade. Annual numbers of merchant ships in the 1500s reached 1,000.

By 1562 the tower height was raised two floors (approximately 10 meters), and in 1577 an artillery bastion named the “Wreath” (for its round shape, of course!) was added at the request of Gdansk city authorities, concerned about the tower’s defensive capabilities. By the 1500s artillery had become more powerful, an increasingly important part of warfare at the time. The Wreath surrounded the medieval tower, and the cannons were placed on two floors with alternating firing ports. As a result, it could fire in a 360-degree arc.

From 1586 ~1602 four brick bastions were built around the Wreath and called “Fort Carre” (French: “square”). In each of the four corner bastions, casements were built. These provided sheltered paths to the corners, plus stored resources needed to withstand sieges, as well as being shelters and division rooms. Officers’ quarters were built along the Wreath, with rooms above for offices, bedrooms. Kitchens and pantries were below. Some of these quarters are nicely restored today (2025)! Finally, the whole thing was surrounded by a moat fed by the Martwa Wisła river.  We know the fortress was well respected in its time because in 1563 Price Eric of Brunswick, fighting against Gdansk, abandoned his plan to besiege Wisłoujście.

Even so, given all the riches of trade and amber, Gdansk was attacked age after age. Wisłoujście saw its share of action, frequently requiring rebuilding. For example, it was bombarded by the Swedes (1627), the Russians (1734), Prussians (1793 & 1814)), Napoleonic France (1807).  

You may have heard of the famous Vasa ship in Stockholm? A terrific example of medieval ship building, amazingly preserved underwater in Stockholm harbor for centuries, raised and now on display. Recall that it was built (and sank) in 1628, part of Sweden’s wars around the Baltic, including here in Gdansk. While that great ship sank before leaving Stockholm, it was meant to be one of the replacements for ships lost in the Battle of Oliva, for example the flagship “Tigren” and galleon “Solen.” You see, in 1623, the cousins Sigismund III Vasa (king of Poland, and Sweden (1592 ~ 1599)) and Gustavus Adolphus (King of Sweden 1617 ~ 1632) began having a tiff over who should rule Sweden and pan-Baltic states (such as Poland & Lithuania).

Gustavus Adolphus based blockading warships near Wisłoujście to strangle Gdansk trade in response to Sigismund’s demand that he renounce the Swedish throne. Then, in 1627 the Polish-Lithuanian Commonwealth navy sallied forth from Wisłoujście and bested Sweden’s, capturing the flagship “Tigern” and taking it to the fortified lighthouse! As for the Solen, Captain and Vice-Admiral Alexander Forath blew it up when he saw the ship boarded and about to be captured. Little wonder then that Gustavus was reportedly very anxious for the delivery of his new warship, the Vasa! Below is a depiction of the battle where the Wisłoujście fort is in the lower right, plus the fairway the bottom center.

Unsurprisingly, with so much fighting over the centuries, the tower was rebuilt many times. Each rebuilding added a slightly different design to the top.

Not only the tower! Starting with the war with Sweden (in the 1620s), Wisłoujście expanded even further with Dutch style earthwork bastions surrounding Fort Carre. In 1673, the fort reached its largest size, with multi-ring defenses, moats, and bastions on both sides of the Martwa Wisła river. This made an effective defense structure, as well as a choke point in and out of Gdansk’s port. Most of the outer ring is gone today, and what remains is currently (in 2025) in ruins. The site is marked with keystones from 1870, matching building from elsewhere in downtown Gdansk (for example “Napoleon Reduit,” Posredini, Zbawiciel and Jerulselm bastions). Equally, there is a Napoleonic barracks that houses a nice timeline, displays and artifacts discovered on site. (We hope you’ve joined us for the It’s in the Signs walkabout on site!)

While its usefulness as a fort declined in early modern times, it was still an appreciated decoration at the mouth of the river. Sadly, like many other sites in Gdansk, it was destroyed in 1945 as the Soviet Red Army bombed the city, attacking the Nazis. Then, in 1953 a major storm caused further collapse. The lighthouse itself was reconstructed in 1962. Nearby facilities for manufacturing and chemical processing (mainly sulfur) thwarted plans to further rehabilitate Wisłoujście.

In 1974 the site was taken over by the Museum of Gdansk, which has been repairing and restoring it ever since. This has been a slow process because certain rights were granted to factories, such as the “Dagoma” fruit and vegetable processors, who stored barrels of product within Fort Carre! As a result, the fort was dilapidated in the 1990s. However, with the ascension of Poland into the European Union, work began in earnest. By 2009 the restoration was complete enough to reopen to tourists. Since then, restoration has continued and Wisłoujście is operated as a museum. Among the major efforts underway now is the restoration of the lighthouse top as it was in the 1721-1889 period (see comparison of tops above and plans below).