shape of the tail of a star (the so-called "Hornewerck"). In November 1802 the House of Mecklenburg under the leadership of Duke Friedrich Franz I came in possession of the property of the Holy-Spirit-Hospital in Lübeck. The Swedish portion of the island was leased for 99 years by the Duke in 1803. It officially remained in Swedish possession until 1903, when it completely returned to Mecklenburg. Since the 17th century Poel has been connected to the mainland with dams and bridges. Since 1927 the island has been connected to the mainland by a causeway. In 2003 a sister city treaty was signed with Hammarö Municipality, an island in lake Vänern in Sweden. Nearby Walfisch island was also fortified. References External links German islands in the Baltic Islands of Mecklenburg-Western Pomerania Geography of Mecklenburg Nordwestmecklenburg Populated coastal places in Germany (Baltic Sea)