Frederick William I restricted enrollment in the officer corps to Germans of noble descent and compelled the "Junkers", the Prussian landed aristocracy, to serve in the army, Although initially reluctant about the army, the nobles eventually saw the officer corps as its natural profession. Until 1730 the common soldiers consisted largely of serfs recruited or impressed from Brandenburg, Pomerania and East Prussia, leading many to flee to neighboring countries. In order to halt this trend, Frederick William I divided Prussia into regimental cantons. Every youth was required to serve as a soldier in these recruitment districts for three months each year; this met agrarian needs and added troops to bolster the regular ranks.