Later the strongest of Sogdian city-states of the Fergana Valley rose to prominence. After the 1st century BC, these cities became home to the traders of the Silk Road and grew wealthy from this trade. The steppe nomads were dependent on these settled people for a wide array of goods that were impossible for transient populations to produce. The nomads traded for these when they could, but because they generally did not produce goods of interest to sedentary people, the popular alternative was to carry out raids.