Then the river-god grew very angry. His green robe changed its color to that of the black of the sea in a storm, and his voice was as loud as that of a mountain cataract. Achelous could be almost as powerful as Hercules when he was angered.
"How do you dare claim this royal maiden?" he roared, "you, who have mortal blood in your veins! I am a god and the king of the waters. Wherever I take my way over the earth grains and fruits ripen and flowers bud and bloom. The Princess Dejanira is mine by right."
Hercules frowned as he advanced toward the river-god. "Your strength is only in words," he said scornfully. "My strength is in my arm. If you would win Dejanira, it must be by hand-to-hand combat." So the river-god threw off his garments and Hercules his lion's skin, and the two fought for the hand of the princess.
It was a brave and valorous battle. Neither yielded; both stood their ground. Achelous slipped in and out of Hercules' mighty grasp a dozen times, but at last the hero's powerful strength was too much for this god who had to depend upon adroitness only. Hercules gripped the river-god fast by his neck and held him, panting for breath.
Then Achelous resorted to the trickery that he knew. He suddenly changed his form through the magic arts he could practise to that of a long, slimy serpent. He twisted out of Hercules' grasp and darted a forked tongue out at him, showing his fangs. Hercules was not yet undone. He only laughed scornfully at the serpent and grasped the creature by the back of its neck, ready to strangle it.
Achelous struggled in vain to escape and at last resorted once more to sorcery. In a second the serpent had changed its form to that of a ferocious, roaring bull. It charged upon Hercules with lowered horns. But the hero was still unvanquished. He seized hold of the bull's horns, bent its head, gripped its brawny neck and threw it, burying its horns in the ground. Then he broke off one of the horns with his iron strong hand and held it up in the air shouting,
"Victory! Dejanira is mine!"
Achelous returned to his own shape and, crying with pain, ran from the castle grounds where the combat had taken place and did not stop until he had plunged into a cooling stream. It had been right that Hercules should triumph, for his was the strength of arm, not of trickery.
The Princess Dejanira came to him and with her the goddess of plenty, Ceres, to give the conqueror his reward.