An Assassin cell is a unit of the modern organizational structure of the Assassin Brotherhood, in use since the 20th century. Composed of smaller groups of Assassins spread out across the globe, it is a successor to the former system of guilds devised by the legendary Assassin Mentor Altaïr Ibn-La'Ahad. In contrast to guilds, cells reflects a far more decentralized command structure, though like their antecedent, there was generally one per major or strategic city.