This resplendent Thankga relates the whole historical, cultural, philosophical and religious synthesis achieved by Tsong Khapa and embodied in the Gelug Order. To the practitioner, this entire vision of the Great Assembly Tree would bee seen by the mind's eye in space, streaming forth a radiance of rainbow spiritual light. Such a vision creates a field of secure clarity and penetrating brilliance, in which a person may effectively contemplate the subject of his practice. This icon is thus a major tool of practice as well as an object of veneration and and worship. The particular form of this representation, special to the Gelugpa, appears to have been developed by the 18th century.