From White Wolf Wiki:
"Founded in 1923 by Maxwell Anderson Mercer, the Æon society is a benevolent organization dedicated to the betterment of mankind. Beginning as a gentlemen's club, by the time of the Trinity Era, the Æon Trinity is, directly or indirectly, the most powerful organization in settled space."
The Æon Universe depicts the events surrounding an alternate history, that branches out of our own in the early 1920s, as several "special" people begin appearing all around the world.
The family covers 3 different points in time (each with a game on its own) bounded together through the same history.