Helena Hamerow suggests that the prevailing model of working life and settlement, particularly for the early period, was one of shifting settlement and building tribal kinship. The mid-Saxon period saw diversification, the development of enclosures, the beginning of the toft system, closer management of livestock, the gradual spread of the mould-board plough, 'informally regular plots' and a greater permanence, with further settlement consolidation thereafter foreshadowing post-Norman Conquest villages. The later periods saw a proliferation of service features including barns, mills and latrines, most markedly on high-status sites. Throughout the Anglo-Saxon period as Hamerow suggests, "local and extended kin groups remained...the essential unit of production". This is very noticeable in the early period. However, by the tenth and eleventh centuries, the rise of the manor and its significance in terms of both settlement and the management of land, which becomes very evident in the Domesday Book.