Reckoning from his appointment on 12 May 688, at about the age of 46, Ceolfrith, who had already ruled Jarrow for several years held office as sole abbot of the two foundations for just over 28 years. These years from 688 to 716, within which some of the earlier works of Bede were written, may well have been among the most fruitful and prosperous in their whole history. Under Ceolfrith's rule, with the support of a sympathetic king, new oratories were built, additions were made to the plate and vestments of the churches, the size of the library was doubled, fresh endowments of land were received, another mission was sent to Rome and the communities themselves expanded so greatly that when Ceolfrith laid down his office to go to Rome in 716 he left behind him in the two monasteries more than 600 monks with lands, ‘that according to the customary reckoning of the English might support almost 150 households’. The original endowments given by Ecgfrith amounted, if we take Bede's figure for Jarrow, to the land of 110 households. Shortly before his death Benedict Biscop was negotiating with King Aldfrith for the acquisition for Jarrow of an estate which was valued at 8 households and lay close to the river Fresca.