With the conversion of much of England in the sixth and seventh centuries, there was an explosion of local church building. English monasteries formed the main basis for the church and were often sponsored by local rulers. They took various forms, including mixed communities headed by abbesses, bishop-led communities of monks, and others formed around married priests and their families. Cathedrals were constructed, staffed either with secular canons in the European tradition or, uniquely to England, chapters of monks. These institutions were badly affected in the ninth century by Viking raids and predatory annexations by the nobility. By the start of the tenth century, monastic lands, financial resources and the quality of monasteries' religious work had been much diminished. Reforms followed under the kings of Wessex who promoted the Benedictine rule then popular on the Continent. A reformed network of around 40 monastic institutions across the south and east of England, under the protection of the king, helped re-establish royal control over the reconquered Danelaw.