The preparations which the leaders had been pushing on during several weeks were completed in April, 1204, and that day was chosen for an assault upon Constantinople. Instead of attacking simultaneously a portion of the harbor walls and a portion of the landward walls, Venetians and crusaders alike directed their efforts against the defences on the side of the harbor. The horses were embarked once more in the _huissiers_.[39] The line of battle was drawn up; the huissiers and galleys in front, the transports a little behind and alternating between the huissiers and the galleys. The whole length of the line of battle was upward of half a league, and stretched from the Blachern to beyond the Petrion.[40] The Emperor's vermilion tent had been pitched on the hill just beyond the district of the Petrion, where he could see the ships when they came immediately under the walls. Before him was the district which had been devastated by the fire. On the morning of the 9th the ships, drawn up in the order described, passed over from the north to the south side of the harbor. The crusaders landed in many places, and attacked from a narrow strip of the land between the walls and the water. Then the assault began in terrible earnest along the whole line. Amid the din of the imperial trumpets and drums the attackers endeavored to undermine the walls, while others kept up a continual rain of arrows, bolts, and stones. The ships had been covered with blanks and skins so as to defend them from the stones and from the famous Greek fire, and, thus protected, pushed boldly up to the walls. The transports soon advanced to the front, and were able to get so near the walls that the attacking parties on the gangways or platforms, flung out once more from the ships' tops, were able to cross lances with the defenders of the walls and towers. The attack took place at upward of a hundred points until noon, or, according to Nicetas,[41] until evening. Both parties fought well. The invaders were repulsed. Those who had landed were driven back, and amid the shower of stones were unable to remain on shore. The invaders lost more than the defenders. Before night a portion of the vessels had retired out of range of the mangonels,[42] while another portion remained at anchor and continued to keep up a continual fire against those on the walls. The first day's attack had failed.