Wismar was founded around 1226 under Henry Borwin I, one of the lords of Mecklenburg - a dynasty of Slavic Obotrite descent that had thrown in with the German world. The oldest surviving town document, from 1229, already takes its civic rights for granted, which means the place was working as a town before anyone bothered to write it down. The harbour explains why. A natural anchorage sits behind a sheltering promontory, roughly halfway between Lubeck and Rostock, with the low green island of Poel closing the bay off from the open Baltic. In 1259 Wismar joined Lubeck and Rostock in a defensive agreement aimed squarely at Baltic pirates, and other towns of the northern Empire followed. Out of that arrangement - mutual protection first, coordinated commerce afterwards - grew the Hanseatic League. Wismar spent the next two centuries as a trading hub and a centre of wool processing. Plague killed some two thousand of its people in 1376. It stayed prosperous anyway.

The Peace of Westphalia gave Wismar to Sweden in 1648, and the arrangement amounted to far more than a garrison. Holding territory inside the Holy Roman Empire entitled Swedish kings, as imperial princes, to a seat in the Imperial Diet. From 1653 the Furstenhof in Wismar housed the supreme court for every Swedish dominion in the Empire, which made this modest port, for a while, a legal capital. Field Marshal Erik Dahlbergh rebuilt the defences into a full all-round fortification system, and sections of his earthworks still shape the ground in the Lindengarten east of the old wall. None of it settled the question of ownership: Danish forces besieged and captured the town in 1675, during the Scanian War. What lasted best was not military. It was architectural - a distinct layer of seventeenth- and eighteenth-century Swedish building sitting over the brick Gothic, and a lasting habit of looking north.

In 1922 F. W. Murnau came here to film a vampire, and Wismar became Wisborg. The establishing shot of Nosferatu looks down from the tower of the Marienkirche over the market square, with the Wasserkunst - the ornate waterworks pavilion imported from Holland in 1602 - sitting in the middle of the frame. The Wassertor appears, and the south side of St Nicholas', the Heilig-Geist-Kirche and the harbour. The association never came loose. When Werner Herzog remade the film in 1979 he kept Wismar as the setting but could not shoot in the town, so he moved production to Delft and Schiedam and let two Dutch cities impersonate a German one. Shadow of the Vampire, the 2000 film about the making of the 1922 film, is set here too. Wismar has now been haunted on screen for over a century, always by proxy, always in its own streets.

The war arrived as bombs and as forced labour. A subcamp of the Nazi prison at Butzow-Dreibergen operated in Wismar, and the people held in it were worked for an economy that had no intention of releasing them. Allied raids wrecked much of the old town; St George's was gutted by blockbuster bombs on 14 April 1945. Three weeks later, on 2 May, the 1st Canadian Parachute Battalion of the British 6th Airborne Division reached the town under James Hill, having pushed this far east under Operation Eclipse in order to meet the Soviets rather than fight them. Montgomery and Marshal Rokossovsky met here on 7 May. Then the lines agreed at Yalta took precedence, the British pulled back, and on 1 July 1945 Wismar passed into the Soviet occupation zone.

East Germany made Wismar its second port after Rostock, built ships here, and promised to restore the bombed churches. That promise went largely unkept. St Mary's, whose tower had anchored the skyline for centuries, was partially razed in 1960, and the tower alone still stands - attached to nothing, the most eloquent ruin in Mecklenburg. Restoration came after 1990 and came thoroughly, and in 2002 UNESCO inscribed the historic centres of Stralsund and Wismar together as a World Heritage Site. What you walk into now is a market square of ten thousand square metres, among the largest in northern Germany, ringed by gabled merchant houses with the Wasserkunst still running at its centre. St Nicholas', built between 1381 and 1460, came through intact. St George's finally reopened in 2010, sixty-five years after the bombs. Around forty-three thousand people live here, and the shipyard's tall white-and-blue assembly hall still marks the harbour.