The history of the town of Mokolo, in the heart of the land of the Mafa (in northern Cameroon), exhibits a specific pattern of urbanisation that seems characteristic of Islamic frontier zones generally in Africa. The town was founded as a settlement for converted slaves towards the end of the nineteenth century by Fulbe chiefs who regularly raided the area. Since that time urbanisation has largely gone hand in hand with Islamisation. It has involved, therefore, a marked change of identity for Mafa converts in the town, with drastic consequences for their relationship with their areas of origin in the mountains. The article emphasises, moreover, that the implications of Islamisation/urbanisation differ along gender lines. Although for both men and women the Muslim community in town provided specific forms of social security, the motives for migration, and the ways men and women were included in the urban community, differed sharply. In the 1980s, owing to political changes at the national level, the pressure to convert to Islam decreased throughout northern Cameroon. Since then the number of migrants to town who do not convert has increased rapidly. Mokolo used to be a Muslim town. In the 1990s, however, it has become more and more a Mafa town, and thus symbolises the revival of Mafa ethnicity as a truly region-wide force.