As the Bantu-speaking agriculturists of the Uganda area spread and multiplied over the centuries, they evolved a form of government by clan chiefs. This kinship-organized system was useful for coordinating work projects, settling internal disputes, and carrying out religious observances to clan deities, but it could effectively govern only a limited number of people. Larger polities began to form states towards the end of the first millennium CE, some of which would ultimately govern over a million subjects each. More extensive and improved cultivation of Bananas (high-yield crops that allowed for permanent cultivation and settlements) by Bantu groups between 300 and 1200 CE helped this process.