The Isu created the First Civilization artifacts in Assassin's Creed lore.
The Isu are an advanced civilization that existed on Earth before recorded human history. They created humanity and built powerful devices commonly called Pieces of Eden, including Apples of Eden, Staves, and the Sword of Eden. These artifacts can influence perception, behavior, or physical forces within the fiction of the series.
Humanity eventually rebelled against Isu control, while a catastrophic solar event devastated both civilizations. Survivors and inherited records later became the basis for many myths, religions, and legends. Assassin's Creed uses this fictional prehistory to connect its historical adventures with a science-fiction narrative.
The Isu were once frequently described as the First Civilization or Precursors. “Ancients” is not the standard name for them in the main series, and the historical Assassins themselves are human organizations that arise much later. The artifacts are therefore not ordinary relics made by medieval or classical societies.