Ancient magic

Two broad types of magic are proven to exist: magic innately possessed by humans, and magic innately possessed by spirits.
In ancient times, there was a widespread belief in a third type of magic, innate in the natural world. It was believed that humans could harness this magic through rituals and spells, manipulating the unseen forces of the world to accomplish what their innate magic could not. Though the results were rarely immediately (if ever) apparent, many people believed in this "natural magic" and employed it for things ranging from the grand (coercing fate, curing corruption) to the utterly mundane.
Attitudes toward this sort of magic varied by time, place, and purpose. Necromancy was generally seen as bad. Rituals to accomplish things the gods could do (e.g., changing the weather) were sometimes seen as an insult to gods and at other times a way to petition them. "Natural magic" was sometimes attributed to spirits, which wasn't necessarily bad unless evil spirits were involved. What ultimately caused its decline, though, was scientific inquiry: it turned out that spirits occasionally took interest in and responded to these human rituals, but aside from that, it was all superstition. (Some rituals, rather then being dismissed as superstition, found their way into accepted religious practice and also stopped being seen as magical.)
Long after the superstitious magic died out, it was "rediscovered" in ancient texts. It became of interest to secret societies who saw it as profound arcane knowledge that had been lost to history (as well as scam artists who could make a profit selling "enchanted" objects inscribed with ancient-looking gibberish). The secrecy and its co-opting by shady (and often fake) practitioners led to a narrative emerging that this "ancient magic" was dangerous and had rightfully been suppressed. At the same time, its proponents came up with reasons why it was unfairly suppressed (the government/religious institutions saw it as a threat, etc.).
Regardless of the view, one thing is clear: belief in these long-forgotten superstitions is re-emerging.