The nine passions are the clearest link between the modern Enneagram and older material, and also the clearest sign that the modern system is a construction. Oscar Ichazo built his scheme on the list of capital vices of the Christian ascetic tradition, the seven of Gregory the Great which descend from the eight logismoi of Evagrius Ponticus, and expanded them to nine by adding deceit for type Three and fear for type Six, neither of which appears in the classical list. The paired virtues are likewise adapted. Ichazo taught this material in Chile in the 1960s and at his Arica Institute from 1970, and it is his synthesis; there is no ancient source in which nine passions are matched to nine types on a nine-pointed figure. Saying so is not a criticism of the system's usefulness, only an accurate statement of where it came from.
A further layer, the tritype, was added later still: Katherine Chernick Fauvre developed the theory in 1994 and 1995, building on scattered remarks by Ichazo and Naranjo but organizing them into a formal model only she published, holding that a person carries one dominant type from each of the three triads, body, heart and head, for twenty-seven possible three-number combinations said to describe a fuller personality than any single type alone. Like the rest of the system's internal machinery, the tritype is a later, datable addition with a named author, not part of Ichazo's or Naranjo's original teaching.