The Greek forces were encamped at Peta in Arta when a force of 7,000-8,000 Ottoman troops attacked their positions.[11] The Ottomans advanced before dawn in a crescent formation with 600 horsemen charging on the right towards the western ridge.[2] The Ottoman cavalry were surprised that no fire was returned, and only when they reached within a hundred feet of the ridge, did the philhellenes and the Greek regulars return fire, bringing down a lethal rain of bullets that cut down the Ottomans, who not used to fighting a disciplined opponent in Greece.[12] Over the next two hours, the Ottomans charged and charged again against the ridge, and were beaten off with heavy losses every time.[13] On the north of the eastern ridge, Albanian irregulars attacked, but were initially repulsed by Bakolas's men.[14] During the conflict, the Greeks and Philhellenes were betrayed by Gogos Bakolas, an old klepht and captain of the armatoloi.[6] According to some accounts, Bakolas deliberately left his right flank unguarded and made no effort to fire upon the Albanians as they advanced on his right flank.