Spread via Heidelberg
Heidelberg, the major catalyst for the idea, had been responsible for its spread through Germany to the Netherlands via Junius and Gomarus, and indirectly to Scotland through Howie and the use of the Heidelberg theology in the academic curriculum. Cambridge Puritanism, as represented by Fenner and Perkins, had also played its part.
Robert Letham, "The Foedus Operum: Some Factors Accounting for its Development," The Sixteenth Century Journal 14 (1983) 465.