Which case, and why?

The Eighth Epistle of the Bodily, Natural [Sciences]: On the Manner of the Generation of Animals and Their Kinds. (3) Chapter explaining the beginning of creation. It is said that when the offspring of the children of Adam had multiplied, grown numerous and spread over the earth, on land and sea, on plain and mountain, going about it in pursuit of their needs and living in safety. Before this they had been restless, fearful and ill at ease because of the great number of beasts of prey and wild animals on the earth, and they used to take shelter on the tops of mountains and hills, fortifying themselves there, and in grottoes and caves. They ate the fruit of the trees, the herbs of the earth and the seeds of plants. They covered themselves with the leaves of trees against heat and cold, wintered in warm lands and summered in cold lands. Then they built fortresses, villages and cities on the plains of the earth and settled in them.