It was a dark-hued harp, small enough for one to travel with.
The Harp that Sings by Itself gently played various old songs—ballads, airs, and lays—of the North. Though it was known to be a unique magical item, its full powers were forgotten by the mid–14th century DR.[note 1]
Some folk claimed that the harp had been owned by Mintiper Moonsilver, the renowned 14th-century bard, but this was widely disputed. The harp had been around for longer than he had and it was confirmed to have been in Silverymoon during the time he traveled the North. (In fact, it had indeed naught to do with Mintiper.)
By the mid-1360s DR, the Harp that Sings by Itself was the prize piece of Halambar Lutes & Harps in Waterdeep, an attraction drawing customers to the store. It stood upon a velvet-draped plinth, high out of reach of thieves and curious hands, and was well protected. Kriios Halambar had no intention of selling it.
Anyone who dared steal the priceless instrument would likely find themselves hunted by agents hired by Halambar to retrieve it, as well as by members of the Harpers.