(£) was rejected due to wanting the castles within the lands, which Richard was not willing to give. In 1200, William did homage for Northumbria, not for Scotland, to Richard's successor, John, apparently to save face. Despite the Scots regaining their independence, Anglo-Scottish relations remained tense during the first decade of the 13th century. In August 1209 King John decided to flex the English muscles by marching a large army to Norham (near Berwick), in order to exploit the flagging leadership of the ageing Scottish monarch. As well as promising a large sum of money, the ailing William agreed to his elder daughters marrying English nobles and, when the treaty was renewed in 1212, John apparently gained the hand of William's only surviving legitimate son, and heir, Alexander, for his eldest daughter, Joan. Despite continued dependence on English goodwill, William's reign showed much achievement. He threw himself into government with energy and diligently followed the lines laid down by his grandfather, David I. Anglo-French settlements and feudalization were extended, new burghs founded, criminal law clarified, the responsibilities of justices and sheriffs widened, and trade grew. Traditionally, William is credited with founding Arbroath Abbey, the site of the later Declaration of Arbroath. The bishopric of Argyll was established (c.1192) in the same year as papal confirmation of the Scottish church by Pope Celestine III. William died of natural causes in Stirling in 1214 and lies buried in Arbroath Abbey. His son, Alexander II, succeeded him as king, reigning from 1214 to 1249. William was not known as "the Lion" during his own lifetime, and the title did not relate to his tenacious character or his military prowess. It was attached to him because of his flag or standard, a red lion rampant with a forked tail (queue fourchée) on a yellow background. This (with the substitution of a 'double tressure fleury counter-fleury' border instead of an orle) went on to become the Royal Banner of Scotland, still used today but quartered with those of England and of Ireland. It became attached to him because the chronicler John of Fordun called him the "Lion of Justice". Marriage and issue Due to the terms of the Treaty of Falaise, Henry II had the right to choose William's bride. As a result, William married Ermengarde de Beaumont, a great-granddaughter of King Henry I of England, at Woodstock Palace in 1186. Edinburgh Castle was her