Bad Buchau () (formerly Buchau; Swabian: Buacha) is a small town in the district of Biberach, Baden-Württemberg, Germany with about 4,000 inhabitants. It is situated near Lake Federsee, which is separated from the town by a wide reed belt. Bad Buchau incorporates the nine villages of Allmannsweiler, Dürnau, Kanzach, Betzenweiler, Moosburg, Alleshausen, Seekirch, Tiefenbach, and Oggelshausen, as well as the outlying farm settlements of Ottobeurer Hof, Bruckhof, and Henauhof. Also part of Bad Buchau is the formerly independent district of Kappel. The official language is German, with day-to-day conversations by the majority of its inhabitants in the Swabian dialect. From the 13th century to the mediatisation of 1803, Buchau had the particularity of being the seat of both an Imperial Abbey and a Free Imperial City, independent of each other. In terms of area, it was one of the smallest such self-ruling cities and its island situation eliminated the necessity to erect city walls and towers. Buchau, however, lost its insular benefits after the water level of Lake Federsee had been lowered on two occasions. History AD 770 – Buchau Abbey was founded in by the Frankish Count Warin and his wife Adelindis, from whom the present "Adelindisfest" takes its name. The church still serves as the parish church. 819 and 857 – Grants for the Abbey are received from the Frankish Kings Louis the Pious and Louis the German respectively. 902 – The three sons of countess Adelindis, Gerhard, Beringer and Reginolf, are killed when attempting to abduct their sister, the Abbess Adelindis, from Buchau's Abbey in order to get her married. Countess Adelindis joins the Abbey in order to atone for her sons' deed and is to this day admired as a great Benefactrix and Saint of the people. She rests together with her slain sons in the crypt of the collegiate church. 1014 or 1022 – A mint and market is mentioned by the Abbey. Buchau appears for the first time as a "Freie Reichsstadt" (Free imperial city). 1417 – The Abbey is declared a secular convent and accepts daughters of the Swabian nobility. 1577 – The Free Imperial City hosts a Jewish Community, which quickly gains prominence under the protection of the city. 1650 – A Jewish cemetery is constructed. 1730 and 1837 – Erection of a synagogue for the growing Jewish community. 1774–1776 – The style of the collegiate church is transformed from Gothic to