In 1907 M. Louis Desplaques described in Le Plateau Central Nigérien a series of large tumuli—pyramids of earth—the burial places of chiefs of a past era. He notes their existence at El Walaji and as far east as Aménaka, near Zinder, on the banks of the Niger near the Bassa rapids, west to Sikassa, and on the banks of the Senegal. On archaeological grounds, supported by a well-known passage from the Arab writer El Behri, he concludes that they were built by “red” or Berber races of the same stratum of population as the ancient inhabitants of the Ghana Empire. “They remain”, he writes, “as the sole witnesses of the activity, the industry, and civilization of these ‘red’ peoples, whose names and real origin we do not know”.