The university had for long been French-speaking, but Dutch played an increasingly important role in the 20th century. The tensions caused by the continued presence of a French-speaking section of the university grew through the 1960s and led to Flemish students rioting, supported by the population of the Flemish city of Leuven. A comment by a French-speaking social geographer of the university, who suggested that Leuven be included in the officially bilingual Brussels area, caused demonstrations from Flemish citizens and politicians; their main slogan was "Leuven Vlaams – Walen Buiten!"