Uaithne
Uaithne was the name of the magical harp belonging to the Dagda, a prominent god in Irish mythology. It was one of the Four Treasures of the Tuatha Dé Danann, along with the Stone of Fal, the Spear of Lugh, and the Sword of Nuada.
According to legend, Uaithne was capable of playing music that controlled the emotions of those who heard it. It could bring people to tears, make them laugh, or lull them to sleep. In some accounts, it could even manipulate the seasons.
The Dagda was said to have the ability to summon Uaithne to him at will. One famous story involves the Dagda retrieving Uaithne from the Fomorians after they had stolen it. He commanded the harp to play in its proper order of tunes: sorrow, joy, and sleep, which weakened the Fomorians and allowed him to escape with his harp.
The power and importance of Uaithne highlight the significance of music and artistry in ancient Irish culture and mythology.