Spirit’s ley lines, which Annumbra the World Walker used to imprison Erlik One-Eye in the Darkhold, were the source of earthsong, but they didn’t have the music in them (apologies to Kiki Dee) until the Battle of Molten Fire. That epic struggle between Finbardin and Erlik unleashed such titanic force that the very land was scarred. Nyllen the Minstrel sang to the world, healing it and transforming the magik of the ley lines into earthsong. In the Elder Days, channelers could stand in the Stones, hear the earth song and draw upon its power. After the Stones fell, channelers were powerless, though earthmages, people who could hear the earthsong from anywhere, whether or not they were standing in the Stones, had power until the Reckoning, when the world was remade without Spirit’s ley lines.
Sorcery operated on vastly different principles and owed its power to the Flame of Creation which burned in the Void. Harnor, the god of magik, built the Spires of Thought in Heaven to capture and transform the energy radiating from the Flame, energy which could pierce the Primal’s Girdle. After passing through the Spires, the sorcerers of the Elder Races could absorb the energy and use it to accomplish great feats of magik.
After the Reckoning, Harnor built the Towers of Sorcery on Sangrar. These towers dampened the Spires’ output enough to make it safe for human sorcerers, who were far frailer than their counterparts from the Elder Races when it came to magik. Without the Towers, tapping into the Spires would burn out all but the strongest of human sorcerers.
During the Age of Mankind, Algerin Bluefist came up with the concept of duel arcane, though he didn’t know it at the time. With a little help from a beardless stranger, he managed to turn his accidental discovery into the gold standard for dueling wizards.
A form of magik unique to the Pearl Throne of Sangrithar was god-fire, which was the legacy Thar who was Umbar left for his heirs. From Averanda, the first Queen to Torval Waverider, God-Emperor in the time of Hali, each and every one of them wielded god-fire.
Lastly, I’ve included a short list of relics from the Elder Days. Back then, magik was commonplace. Everyone had at least a little bit of sorcery and some were positively dripping with it. Remember Mrs. Weasley’s house? Same thing. If I listed all the magikal items available back then, the list would go on for miles. This abbreviated list only names the most powerful ones.