feudalism was the structuring of society based upon hierarchical relationships whereby the holding of land was exchanged in return for service, generally military, or labor. In addition to military service or labor, the lord would require dues, in either coinage, as is generally the case between the monarch and his vassals, or in-kind payment – which was the standard between a lord and the peasantry. In Scotland, this payment was referred to as cáin. The cáin was generally paid in the form of the area's main produce. The term denotes both the regular exaction of an area's revenue by the king, like the Scottish king's exaction of payment in the Southern Uplands, as well as irregular tribute to a superior authority, as was the case in Moray during its period of quasi-independence prior to the mid-11th century. Lord-vassal relationship This system was heavily reliant upon personal relationships and oaths of fealty to maintain political authority and economic domination. Relationships were often left vague when royal authority was limited. For example, the Scottish Crown maintained only loose authority over the Earls of Galloway until Alan, Earl of Galloway, died in 1234 with no legitimate male heir, and Alexander III divided the inheritance among royal supporters with weak familial ties to the earldom. This ambiguity generally supported greater stability at the expense of the royal treasury, as the cáin was collected infrequently, if at all. Scotland and England's relationship was performed in much the same way. The Scottish kings performed homage to the English king for royal lands in Cumbria and Lothian except during periods of English strength or Scottish weakness. For example, the Scottish king William the Lion swore fealty to Henry II of England in 1175 as stipulated in the Treaty of Falaise, which explicitly declared William held all of Scotland as a fief. However, even during these periods of English supremacy, payment was exacted more as tribute for peace than vassalage dues. Richard Oram describes the terms of treaty and their “light touch,” emphasizing the limited economic impact on Scotland: “Henry also demanded control of royal castles in Lothian – Berwick, Jedburgh, Roxburgh, Edinburgh and Stirling, but sought neither men nor money for his wars, nor did he hear appeals from Scottish law courts”. However, this period of ambiguity between the Scottish monarch and his vassals gradually became more formalized during the 11th, 12th, and 13th centuries as the