From the late sixteenth century onwards, expatriates from the British Isles settled in various European–Atlantic ports. These included Catholics who had escaped persecution or displacement, particularly in Ireland during the Elizabethan and Cromwellian regimes. Once abroad, British Catholics worked alongside Protestants, who had been lured by the potential profits that the continental ports could offer, in particular Cadiz and St Malo, the ports of the Spanish and French imperial fleets. Trading with continental Europe was indeed necessary for balancing British trade. England, in particular, traded with Spain, Portugal, and the Netherlands on a consistent basis whereas Scotland and Ireland traded with France and the Flemish territories. The continent demanded English colonial goods, and Dutch and English manufactures, whereas the British Isles absorbed Mediterranean fruit, wine, oil, South American dyes, Indian spices, and Asian pepper. The wealth of names, firms, and ports mentioned in the Aylwards’ papers allow investigation into networks that not only crossed faiths, but also moved beyond national and imperial borders, seeing Spanish goods being exchanged for French and British commodities. With the ultimate aim to satisfy the needs of the British markets, Catholic merchants ensured a constant relation with the continent. Therefore, their role in British commerce cannot be disregarded.

The Catholic merchants working with the Aylwards were ordinary transatlantic traders and their careers do not stray from the path pursued by many merchants of the time. Initially, they developed their careers with co-religionists and family. Religion in fact allowed them to settle in Spain and to tap into other Catholic networks already established in various European ports. However, in order to operate in those vast waters, wider networks were needed, and the Aylwards and their associates worked with anyone deemed trustworthy, Catholic or not, meaning that deals were closed with Protestants as much as with co-religionists. Catholics adapted to the demands of the new markets, moving beyond their religious community, although they did not disregard religious ties. The Aylward family operated in those markets for forty years. This commercial longevity allowed them to work with hundreds of different partners and firms. Their papers allow for a reconstruction of their commercial and financial activities and therefore an increased understanding of their role in commerce. Likewise, their papers allow for investigation into the role played by Catholics within the British mercantile community.