The War of Silver and Iron was a major conflict between the Garou and the Fae during 800 BCE in Ireland and started when the local Garou discovered that the Fae had used them in the War of Seasons. The Garou slaughtered every fae they found and taught humanity about the restricting power of cold iron. The Fae answered by teaching humanity the power of silver and such spread the usage of these metals among the humans, giving them the tools to ward off the supernatural.
The War of Silver and Iron ended when the whole conflict proved to be too expensive for the Fae and they withdrew into Arcadia. After the last werewolf who remembered the conflict had died, they eventually returned.