The Siege of Thebes was a battle that occured between the Army of Anubis and the Sumerian armies of Thebes.
The Scorpion King Invades the first time
In the year 3067 B.C, Mathayus had reached Thebes with his men and had intended to fell the city in the 3067 B.C, conquering it as part of his empire; leading his men to attack Thebes, Mathayus fought with his troops against a number of soldiers of Thebes for seven years before he and his warriors were finally compelled to admit defeat and wander off into the desert of Ahm Shere. Mathayus accepted his defeat quietly, with a sour, displeased look about him as he and his troops wandered on.
The Scorpion King Invades a second time
The Scorpion King was given command of Anubis's army in exchange for his soul, which he used to invade Thebes, and burn it to the ground. Seven years before, the Scorpion King had been defeated, along with his armies, and expelled out into the deserts of Ahm Shere, but the Scorpion King had managed to strike a bargain with the god of mummification, Anubis, promising his soul and a golden pyramid in exchange for the sparing of his life. The jackal god allowed the Scorpion King to live and gave him the chance to conquer once more, giving him his Army to command it in his conquests. After many campaigns throughout the lands, the Scorpion King returned to Thebes to defeat its forces, taking the people of Thebes by surprise.
Once he had completed his quest, Anubis took the Scorpion King's soul and returned his Army back to the sands from which they came, where they lay silently until they would be called to battle again.