True Magic. This is a different mystery than magery. Magi call the events that are unachievable by magery and science in that age True Magic. If that event could be achieved by time and resources, then no matter the difficulty, that event will not be seen as True Magic.
When the civilization of mankind was still young, all magery had been True Magic. But along with the advancement of science, the number of things that "could be done" by people had increased, and in exchange, True Magic diminished.