 In 1377 the cities of Freiburg, Basel, Colmar, and Breisach entered into a monetary alliance known as the "Genossenschaft des Rappenpfennigs" (Rappenpfennig Collective).This alliance facilitated commerce among the cities and lasted until the end of the sixteenth century.There were 8,000–9,000 people living in Freiburg between the thirteenth and fourteenth centuries, and 30 churches and monasteries.