Which organization is known as the ancestors of the Assassins in Assassin's Creed Origins?

The Hidden Ones are presented as the ancestors of the Assassins in Assassin's Creed Origins.

Bayek and Aya establish the Hidden Ones after the death of their son and their experiences with the political forces controlling Ptolemaic Egypt. The organization is designed to oppose the Order of the Ancients, a secret network seeking influence over rulers and institutions.

Origins shows the early principles that later define the Assassin Brotherhood: working from the shadows, resisting domination, and protecting people's freedom of choice. The familiar Assassin insignia and creed are linked to this formative period, although the organization has not yet developed the exact identity used in later centuries.

The Order of the Ancients should not be used as the answer because it is the opposing faction. In later games, the Order of the Ancients is connected to the Templar tradition, while the Hidden Ones evolve into the Assassins known from the medieval storyline.