The medieval towns of Wismar and Stralsund were major trading centres of the Hanseatic League in the 14th and 15th centuries. In the 17th and 18th centuries they became Swedish administrative and defensive centres for the German territories. They contributed to the development of the characteristic building types and techniques of Brick Gothic in the Baltic region, as exemplified in several important brick cathedrals, the Town Hall of Stralsund, and the series of houses for residential, commercial and crafts use, representing its evolution over several centuries. Due the valuable remnants of the Hanseatic time, Brick Gothic, renaissance, baroque, historicist and Jugendstil buildings Stralsund old town island and near Wismar are today a UNESCO World Heritage Site.
The heart of the old town is the Old Market Square (Alter Markt), with the Gothic Town Hall (13th century). Behind the town hall soars the imposing Nikolaikirche (St. Nicholas' Church), built in 1270–1360. The square is surrounded by houses from different periods, including the Gothic Wulflamhaus (a 14th-century patrician house, today a restaurant), and the Baroque Commandantenhus of 1751, the old headquarters of the Swedish military commander.
In the Middle Ages, the Stralsund area was part of the West Slavic Principality of Rügen. In 1168, the Principality of Rügen became a part of Kingdom of Denmark. In the course of German Ostsiedlung, many German settlers, gentry and merchants were called into the principality, and eventually populated the Strale settlement. Merchants from other countries as well as locals were attracted to the area and made up for one third of the town's population. The Danish navy used the isle as well. When the settlement had grown to town size, prince Wizlaw I of Rügen granted Lübeck law to 'our town Stralow' in 1234, although a significant settlement had existed long before the formal founding. In 1240, when the prince gave additional land to the town, he called it Stralesund.
The success of the settlement challenged the powerful Free City of Lübeck, which burnt Stralsund down in 1249. Afterwards the town was rebuilt with a massive town wall having 11 town gates and 30 watchtowers. The Neustadt, a town-like suburb, was merged to Stralsund by 1361. Schadegard, a twin town to Stralsund also founded by Wizlaw I nearby, but was not granted German law, served as the principal stronghold and enclosed a fort. It was given up and torn down by 1269 under the pressure of the Stralsund Bürger.
In 1293 Stralsund became a member of the Hanseatic League. A total of 300 ships flying the flag of Stralsund cruised the Baltic Sea in the 14th century. In 1325, the Principality of Rügen became part of the Duchy of Pomerania, Stralsund however maintained a considerable independence.
In the 17th century, Stralsund became a theatre in the Thirty Years' War. In the Battle of Stralsund (1628), the town was besieged by Albrecht von Wallenstein after the council refused to accept the Capitulation of Franzburg. Stralsund resisted with Danish and Swedish support. The Swedish garrison in Stralsund was the first on German soil in history. With the Treaty of Stettin (1630), the town became a major Swedish fort in the Duchy of Pomerania.
After the war, the Peace of Westphalia (1648) and the Treaty of Stettin (1653) made Stralsund part of Swedish Pomerania. Lost to Brandenburg in the Battle of Stralsund (1678), it was restored to Sweden in the Treaty of Saint-Germain-en-Laye (1679). In the Great Northern War in 1715 Charles XII led the defence of Stralsund for a year against the united European armies. Stralsund remained under Swedish control until the Battle of Stralsund (1807), when it was seized by Napoleon Bonaparte's army. Seized by Ferdinand von Schill's freikorps in 1809, it was subsequently re-gained by France, with Schill killed in action. In the Congress of Vienna (1815), Stralsund became a part of the Prussian Province of Pomerania and the seat of a government region resembling the former Swedish Pomerania. From 1949 until German Reunification in 1990, Stralsund was part of the German Democratic Republic.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.