Alexander the Great fought many battles throughout his life, and all held some significance in his long term plans, but his first battle against Darius, the Persian ruler, was very important for both his campaign, and his men's morale. Although it had a shaky start for Alexander and his men were out numbered, Alexander proved once again his prowess on the battlefield, eventually forcing Darius to flee.
In 333BCE Alexander had won his first major battle in Persia, at Granicus, but he had yet to face the Persian ruler Darius. He and his army marched south through Asia Minor conquering cities, as Alexander travelled through Phoenicia he passed by and conquered the city of Issus. Here he left his sick and wounded to recover, which unfortunately turned out to be a poor decision for those left behind. As Alexander travelled south, on the coastal side of the mountains, Darius waited in a strategically chosen location on the far side of the same range, waiting for Alexander.
Unfortunately for Darius, Alexander fell ill and his travel was long delayed, not to mention he was on the wrong side of the mountains. So Darius followed his adisors advice and marched his army across the mountain range to com up behind Alexander. Arrian confirms that when "Alexander heard the report that Darius was in his rear [he] did not believe the report". He sent a ship back, which returned to confirm the information. Alexander promptly turned his armies and marched back towards Issus. Meanwhile Darius had slaughtered the sick and wounded of Alexander's army, all those left at Issus, and continued towards Alexander. The two armies met across the river Pinarus, at a place where Darius could not easily use his numerical advantage.
In a narrow field between the mediterranean...