This chapter describes the development of the “military province” of Raetia. So far, settlement continuity under the Roman Empire has only been proven for the pre-Alpine and Alpine zones. The Romans occupied the northern foothills of the Alps in the course of the Alpine campaigns. Until the mid-first century ce , Rome fortified the Danube as a northern border with military camps. Under the Flavians, especially from Domitian onward, areas north of the Danube were occupied. From this time on, we find more civil settlements, some of which emerged from former military installations; there was also large scale expansion through agriculture. The northernmost expansion of the limes was under Antoninus Pius, but the Marcomannic Wars followed: Germanic invasions, civil wars, and the loss of the Agri Decumates between the Danube and the limes mark the end of the middle Imperial period in the second half of the third century in Raetia.