St. Willibrord was a Northumbrian monk who brought Christianity to the Low Countries in the 7th century and became the first Archbishop of Utrecht in 695. The Anglican and Old Catholic Churches have adopted him as the patron of their relations, which have always been close. To strengthen these links, the first Willibrord Society was founded in England in 1908. Full church communion was achieved when the Bonn Agreement was signed in 1931.
Today the Willibrord Societies in several European countries work to apply this agreement in everyday church life.