"Also to be Prince of Ithilien, the greatest noble after Dol Amroth in the revived Numenorean state of Gondor, soon to be of imperial power and prestige, was not a 'market-garden job' as you term it. Until much had been done by the restored king, the P. of Ithilien would be the resident march-warden of Gondor, in its main eastward outpost - and also would have many duties in rehabilitating the lost territory, and clearing it of outlaws and orc-remnants, not to speak of the dreadful vale of Minas Ithil (Morgul). I did not, naturally, go into details about the way in which Aragorn, as King of Gondor, would govern the realm. But it was made clear that there was much fighting and in the earlier years of A.'s reign expeditions against enemies in the East. The chief commanders, under the King, would be Faramir and Imrahil; and one of these would normally remain a military commander at home in the King's absence."
Letter 244, The letters of JRR Tolkien