The External and Internal Cycle  tend  to be treated as a single classification. A preliminary survey indicates that the External and Internal Cycle strata of the Great Perfection is marked by a strong influx of funerary Buddhism, yet lacks the central complex of innovations centered around the idea of an intermediate process of reality postmortem phase.  Most of the External and Internal Cycle texts are found in The Collected Tantras of Vairocana, most likely a twelfth-century collection