In the time of Charlemagne (ruled 768–814), the connection slowly developed between vassalage and the grant of land, the main form of wealth at that time. Contemporaneous social developments included agricultural "manorialism" and the social and legal structures labelled — but only since the 18th century — "feudalism". These developments proceeded at different rates in various regions. In Merovingian times (5th century to 752), monarchs would reward only the greatest and most trusted vassals with lands. Even at the most extreme devolution of any remnants of central power, in 10th-century France, the majority of vassals still had no fixed estates.