The Tigrayans are, despite a general impression of homogeneity, composed of numerous subgroups with their own socio-cultural traditions. Among these there are the Agame of eastern Tigray, mentioned in the Monumentum Adulitanum in the 3rd century; the autonomous Senadegle and Meretta of Akkele Guzay in Eritrea; the Hamasenay, agriculturalists in Hamasen and cattle herders in Humera; the egalitarian Wajjarat of south-eastern Tigray. Many others, sometimes numbering only a few thousands and scattered over several districts, could be listed. Usually they define themselves through common descent, but in some cases also as a political confederacy uniting different groups (such as the Shewatte Anseba on the north-western borders of the Eritrean highlands). Assimilation processes, which still continue, have led to the inclusion of other ethnic (sub-) groups. For example, Agaw settlers in Seraye, the Adkeme Malga became Tigrayans several centuries ago; some Bilin villages near Keren now also belong to the Tigrayans.