In 1714 the Duke made Bach "Konzertmeister" (Concertmaster, a job that paid more money.) He had to write cantatas for church services. In 1717 he was offered a job in the town of Cöthen, where he would earn an even better salary. The Duke was angry and did not want him to go but Bach insisted, so the Duke put Bach in prison for a month. In the end he had to let the musician go.