Treasures of the Danann

Search your library for an artifact card, then
shuffle your library and put that card on top. If
you control four or more legendary artifact you
win the game.
"The Tuatha de Danann came forth from four great
ships, and from each they brought with them a mighty artifact which would shape the future of the lands of
Albion."
-Excerpt transcribed from the Ogham Stones