These crackdowns had the secondary effect of producing a great number of slaves. They were primarily sold through the ports of Sonyo. As Portuguese shipping focused more on Angola, often there were more slaves in Sonyo than could be bought at any one time. This had the effect of often leading the slaves to have to engage in agriculture to sustain themselves. By 1645, Sonyo was a large and prosperous town, rivaling the Kongolese capital. The Sonyo began to assert their independence against the centralization efforts of the Kinlaza, and with Dutch weapons and support, engaged in full-fledged war with Kongo over a period of twenty-five years. This continued to reflect Church politics, as Sonyo began to receive definite Protestant influence, while Kongo remained steadily Catholic.