The medieval British Isles were marked by a lively monastic presence throughout the entire period. Groups of monks, nuns, regular canons and canonesses, and friars established communities even in the furthermost reaches of the territory, and by doing so they came to play an important part in the life, culture, economy, and politics of the region. This paper will provide an overview of the arrival and spread of the different religious orders in England, Ireland,Wales, and Scotland, and by doing so, it will provide some comparative study of the different parts of the British Isles and examine how and when the spread and settlement of the various religious groups manifested itself across the islands, and what their impact was upon their localities and the society around them.