By the beginning of the seventeenth century the Calvinist network, of which the Calandrinis, Burlamachis and Diodatis formed such a prominent part, was at its most extensive. Wealthy Reformed merchants resided in most of the prominent commercial cities in north-western Europe where foreign Reformed churches were permitted to establish themselves or where Calvinists were offered some degree of toleration. Through a series of individual and mass emigrations often involving two generations of the same families, Calvinism had established itself as a truly ‘transnational’, European faith.