became French), whereas the Franks in the Low Countries retained their language, which would evolve into Dutch. The current Dutch-French language border has (with the exception of the Nord-Pas-de-Calais in France and Brussels and the surrounding municipalities in Belgium) remained virtually identical ever since, and could be seen as marking the furthest pale of gallicization among the Franks. Convergence The medieval cities of the Low Countries, which experienced major growth during the 11th and 12th centuries, were instrumental in breaking down the already relatively loose local form of feudalism. As they became increasingly powerful, they used their economical strength to influence the politics of their nobility.Encyclopædia Britannica Online; entry 'History of the Low Countries'. 10 May. 2009;The development of a town's autonomy sometimes advanced somewhat spasmodically because of violent conflicts with the prince. The citizens then united, forming (sometimes called communes)—fighting groups bound together by an oath—as happened during a Flemish crisis in 1127–28 in Ghent and Brugge and in Utrecht in 1159. During the early 14th century, beginning in and inspired by the County of Flanders, the cities in the Low Countries gained huge autonomy and generally dominated or greatly influenced the various political affairs of the fief, including marriage succession. While the cities were of great political importance, they also formed catalysts for medieval Dutch culture. Trade flourished, population numbers increased dramatically, and (advanced) education was no longer limited to the clergy; Dutch epic literature such as (1150), the and (1200) were widely enjoyed. The various city guilds as well as the necessity of water boards (in charge of dikes, canals, etc.) in the Dutch delta and coastal regions resulted in an exceptionally high degree of communal organization. It is also around this time, that ethnonyms such as Diets and Nederlands emerge. In the second half of the 14th century, the dukes of Burgundy gained a foothold in the Low Countries through the marriage in 1369 of Philip the Bold of Burgundy to the heiress of the Count of Flanders. This was followed by a series of marriages, wars, and inheritances among the other Dutch fiefs and around 1450 the most important fiefs were under Burgundian rule, while complete control was achieved after the end of the Guelders Wars in 1543, thereby unifying the fiefs of the Low Countries under one ruler. This process marked a new episode in the development of the Dutch ethnic group, as now