sentences:  On arriving there on April 20, he immediately invested the town with earthworks and subjected it to heavy bombardment.However, despite his efforts, the Greek garrison, aided by raids from the Greek bands behind his lines and resupplied by the Greek fleet despite the Ottoman naval blockade, resisted effectively.In the end, he was forced to call upon the assistance of Ibrahim Pasha of Egypt, whose army had been victorious against Greek forces in the Morea.