These illustrated divine genealogies were product of the New Mythic Symbolism school that first appeared in the Nochet and Boldhome Knowledge Temples around 1624.
The Mythic Symbolism school was a God Learner approach to divine iconography that was popular in Jrustela and Umathela in the 8th and 9th centuries. It was very stylied and took an almost heiroglyphic approach to divine iconography. Largely forgotten in Third Age Genertela, it was rediscovered recently in the Big Rubble by adventurers who made rubbings of a stele found in the ruins of Robcradle. Copies of those rubbings were circulated among various Knowledge Temples, and the style has become popular because of its comparative simplicity and ease.
An influential Grey Lord in Boldhome drew these particular images in 1625, part of series which she claims depicts the relationship and kinship of all the major deities, and was accompanied by a poem describing the origins and genealogies of the gods, called simply Catalogue of the Gods. This text proved influential in the Hero Wars and several heroquesters claimed it as an inspiration.