Questions about the Temples of the Old Gods events

[Draconzis Piertii]

To be clear as I don't know the official name of the even, it is started by finding a temple in space dedicated to an ancient god of your race, then after accepting the quest you find three other temples to decode the messages within, and ending you have a few options with one of which shifting your ethics to spiritualist. I tried searching for it online, but failed to find what I am looking for. What I am needing to know is exactly what triggers this? If it ever occurs, will it only happen at the start of the game, such as the first year? It is really bugging me I can't find the page for it on the wiki.

[UR|wRÅR]

https://stellaris.paradoxwikis.com/Anomaly_events_3#Familiar_Shrine
Is triggered only by
Anomaly project

[Professor H. Farnsworth]

It's just a rare anomaly that can happen once per game.
There's no way of triggering it other than hoping for the anomalies to roll it.

It's not like The Horizon Signal which you can trigger by moving in and out of black hole systems with a science vessel.
- Can be done with unsurveyed, surveyed, as one of your systems, with mines/research stations in the system and starbases. Chance is 0,5% to proc it tho.