The unification of the Frankish kingdom under Clovis I (465–511) and his successors, corresponded with the need for the building of churches, and especially monastery churches, as these were now the power-houses of the Merovingian church. Two hundred monasteries existed south of the Loire when St Columbanus, an Irish missionary, arrived in Europe in 585. Only 100 years later, by the end of the 7th century, over 400 flourished in the Merovingian kingdom alone. The building plans often continued the Roman basilica tradition.