The Aeolian Singers are based in the English county bordered by which county on its north?
Bedfordshire
Title: Popovo (župa)
Passage: In the Middle Ages, the territory of the Popovo field by the Trebišnjica, the northern part of the Ljubinje area, and the southern part of Bobani, was part of the "župa" (county) of Popovo (] ) which was located in the Hum province.  The county bordered with Primorje county to the south, Trebinje area to the east, Dabar and Dubrave counties to the north, and Žaba county to the west.  The Primorje county was later occupied by the Republic of Ragusa.
Title: Aeolian Singers
Passage: The Aeolian Singers, president Peter Skellern, musical director Stephen Jones, rehearsal pianist Anna Le Hair, was established in 1963.  With about 80 members, it is Hemel Hempstead's largest mixed-voice chorus.  While based in Hertfordshire, the singers also perform in major London concert halls and in other parts of Europe.  In recent years they have performed in Ghent, Paris and Provence and visited Mannheim in October 2006, where they performed in two concerts together with the Konzertchor der Stadt Mannheim.  They have a very wide repertoire ranging from Renaissance to contemporary music, and have given several first performances.  They also have a tradition of community and youth involvement.
Title: Hertfordshire
Passage: Hertfordshire ( ; often abbreviated Herts) is a county in southern England, bordered by Bedfordshire to the north, Cambridgeshire to the north-east, Essex to the east, Buckinghamshire to the west and Greater London to the south.  For government statistical purposes, it is placed in the East of England region.
Aeolian Singers Hertfordshire