Stopping eastward revenue drain and boosting commerce funded Egypt’s first independent Muslim state.

Evidence

The second phase began in 254/868, with the arrival in Egypt of Ahmad ibn Tulun. At first a subordinate with strictly limited powers, subject to the au­ thority of his superiors in Baghdad, he succeeded within a few years in creating a virtually independent state—the first in Muslim Egypt. By reducing the drain of revenue to the East and encouraging agriculture and commerce, he accumu­ lated great wealth; with it he built a new capital, the combined fortress, palace and city of al-Qata’i , hard by the site of Fustat. — Bernard Lewis, From Babel to Dragomans, 373