During the course of the 10th century, the West Saxon kings extended their power first over Mercia, then into the southern Danelaw, and finally over Northumbria, thereby imposing a semblance of political unity on peoples, who nonetheless would remain conscious of their respective customs and their separate pasts. The prestige, and indeed the pretensions, of the monarchy increased, the institutions of government strengthened, and kings and their agents sought in various ways to establish social order. This process started with Edward the Elder – who with his sister, Æthelflæd, Lady of the Mercians, initially, charters reveal, encouraged people to purchase estates from the Danes, thereby to reassert some degree of English influence in territory which had fallen under Danish control. David Dumville suggests that Edward may have extended this policy by rewarding his supporters with grants of land in the territories newly conquered from the Danes and that any charters issued in respect of such grants have not survived. When Athelflæd died, Mercia was absorbed by Wessex. From that point on there was no contest for the throne, so the house of Wessex became the ruling house of England.