Migration has always been a big factor in Irish history and from 1600 to 1800 continental Europe was the main destination for tens of thousands of Irish migrants. Significant groupings of Irish migrants and exiles were seeking religious refuge, due to a series of penal laws directed towards Catholics and in operation in Ireland from the sixteenth to the eighteenth century. These laws precluded the establishment of Catholic seminaries in Ireland as they forbade any type of Catholic teaching or education as well as encouraging the banishment of Catholic clergy in general. Various European cities and towns could provide places of support for the education and well-being of Catholic seminarists. Quickly, a network of Irish colleges began to emerge on the continent predominantly in Belgium, France, Italy, Spain and Portugal which educated both clergy and laity. The Irish colleges had the specific task of educating and training students for the priesthood and for the Irish Mission.