Leo was only granted five months in which to prepare for the long-dreaded advent of the Saracens. He spent this time in accumulating vast stores of provisions, recruiting the garrision of Constantinople, and strengthening its fortifications. On the 15th of August Moslemah with an army of 80,000 Saracens appeared on the Bithynian coast; a few days later a Syrian fleet of over 1000 sail appeared in the Propontis, took the army of Moslemah on board, and transported it into Thrace. The Saracen’s land-troops at once commenced the blockade of the capital by land, while part of the fleet moved into the Bosphorus, to post itself so as to block the mouth of the Golden Horn, in which the Imperial navy had taken refuge. Leo delivered his first blow while the Saracen vessels were passing up the Bosphorus; issuing out of the Golden Horn with many galleys and fireships he attacked the enemy as they were trying to pass up the straits, and burnt twenty ships of war. [Sidenote: Moslemah besieges Constantinople.] The Saracen admiral then dropped down to the southern exit of the Bosphorus, and left the northern exit free to the Romans, so that Leo was able to continue to draw supplies from the Black Sea. The blockade of Constantinople was, therefore, imperfect, and we learn without surprise, that while the Saracens in their camp on the Thracian side of the straits suffered severely from the cold of an unusually severe autumn and winter, the garrison within the walls was well fed and also well housed, and continued to grow in self-confidence. Moslemah sent in haste for reinforcements, and the Caliph supported him with zeal; a second land-army marched up from Tarsus to Chalcedon in the spring of 718, and occupied the Bithynian shore of the Bosphorus, while a great fleet from Africa and Egypt joined the blockading squadron, and moored at Kalosagros on the eastern side of the Bosphorus, in order to watch the mouth of the Golden Horn, and stop the communication of the city with the Black Sea.