Bosau () is a municipality on the Great Plön Lake the district of Ostholstein, in Schleswig-Holstein, Germany. It is situated approximately 13 km west of Eutin, and 30 km southeast of the state capital of Kiel. Parishes The following villages belong to the municipality of Bosau: Bichel, Braak, Brackrade, Hassendorf, Hutzfeld, Kiekbusch, Kleinneudorf, Klenzau, Liensfeld, Löja, Majenfelde, Quisdorf, Thürk and Wöbs. St. Peter's Church, Bosau Bosau is particularly well known for its church, dedicated to St. Peter, which was built in 1151/52. It was established during the Christianisation of Slavic East Holstein (Ostholstein). The missionary, Vicelin, was appointed in 1149 by Henry the Lion as the bishop of Oldenburg in Holstein was given Bosau as a temporary seat of office (Amtssitz), where he had a church built in 1151/52. In 1152 Vicelin suffered a stroke and died in 1154 in Neumünster. The priest, Helmold von Bosau, reported this in his Chronica Slavorum. Bosau summer concerts and summer academies For over 40 years, the Evangelical Lutheran Church Bosau has organized the Bosau Summer Concert (Bosauer Sommerkonzerte) in St. Peter's Church. Since 2003, Bosau's church musician and organist, Sergei Tcherepanov, has been the artistic director of the summer concerts. He has designed this series of events to be an attractive festival with a different focus: organ concerts of classical style, days of the alternative organ music "The Organ Dances", concerts, chamber music, choral and solo performances. Since 2008, the summer concerts will be sponsored by a society, the Friends of the Bosau Summer Concerts (Freunde der Bosauer Sommerkonzerte), who will assist in laying on the event. For the first time in 2009 a Bosau International Summer Academy (Internationale Sommerakademie Bosau) was held in parallel with the summer concerts, at which over 35 participants from several countries gave master classes in organ, harpsichord, oboe and baroque violin. The summer academy was also initiated and organised by S. Tcherepanov, but support came especially from the teachers of the Lübeck Academy of Music. The final concerts by the academy students and teachers are an attractive addition to the summer concerts. The summer academy will take place in future every year as part of the summer concerts. Weapons testing In 1939 the company of Hellmuth Walter KG Kiel acquired land by the Plön lake and built their factory's test site in Stadtbek. Here torpedoes and launch systems (Schlitzrohrschleuder, lit. "slotted tube catapult") were tested. This Walter