Za Aliamen settled in Kukia, the capital, and became the first of a long line of Berber kings of the Songhai. The Songhai is a Negro people whose traditional home is Dendi, which lies to the north-west of the confluence of the Gulbin Kebbi and the Niger and not far above the Busa rapids. The king of Songhai was Sonni Ali, an able and ambitious ruler who was not slow to seize the opportunity which Omar offered. Sonni Ali only prevailed over Jenne at the cost of a trying siege of several years. The investing army was constantly forced to change its position by the rise and fall of the waters which till then had always successfully prevented the capture of the city. During a reign of twenty-six years Sonni Ali had transformed a petty kingdom into a formidable empire and at the time of his death his people had become the greatest power in the Western Sudan.