We find similar instances of the remission of jizyah in the case of Christians who served in the army or navy under the Turkish rule. For example, the inhabitants of Megaris, a community of Albanian Christians, were exempted from the payment of this tax on condition that they furnished a body of armed men to guard the passes over Mounts Cithæron and Geranea, which lead to the Isthmus of Corinth; the Christians who served as pioneers of the advance-guard of the Turkish army, repairing the roads and bridges, were likewise exempt from tribute and received grants of land quit of all taxation; [103] and the Christian inhabitants of Hydra paid no direct taxes to the Sultan, but furnished instead a contingent of 250 able-bodied seamen to the Turkish fleet, who were supported out of the local treasury. [104] The Southern Rumanians, the so-called Armatoli, [105] who constituted so important an element of strength in the Turkish army during the sixteenth and seventeenth centuries, and the Mirdites, a tribe of Albanian Catholics who occupied the mountains to the north of Scutari, were exempt from taxation on condition of supplying an armed contingent in time of war. [106] In the same spirit, in consideration of the services they rendered to the state, the capitation-tax was not imposed upon the Greek Christians who looked after the aqueducts that supplied Constantinople with drinking water, [107] nor on those who had charge of the powder-magazine in that city. [108] On the other hand, when the Egyptian peasants, although Muslim in faith, were made exempt from military service, a tax was imposed upon them as on the Christians, in lieu thereof. [109] Living under this security of life and property and such toleration of religious thought, the Christian community—especially in the towns—enjoyed a flourishing prosperity in the early days of the Caliphate.