"Bar" songs?

Via Cranach, a useful clarification of a myth often repeated:

Luther did not use bar songs but rather his own creations and the musical heritage of the church catholic. The term bar refers to the type of staff notation used in medieval musical composing. . . .

The musical notation was simply a repeat sign, known in Luther’s day as a “bar”. ....

A more complete explanation: "Did Luther Endorse 'Bar' Music for the Church?"

Luther’s bar tunes | Cranach: The Blog of Veith