Tanistry is a system of succession used primarily in Gaelic and Celtic societies, where a leader or king is chosen from a pool of eligible candidates rather than through direct inheritance. This method emphasizes the selection of a capable leader, often from the same family or clan, ensuring that the chosen individual is deemed fit to rule. In Tanistry, the process involves a council of nobles or clan members who nominate and elect the next leader, often based on merit and ability. This practice contrasts with primogeniture, where the eldest son inherits the title, allowing for more flexibility in leadership selection.