Daeron

There was an ancient tradition going back to Tolkien's early work that Daeron wandered from Doriath in search of Lúthien, and became lost in the wild East of Middle-earth where he spent long ages making music beside dark lakes and seeking Lúthien in vain despair. The exact date of his departure is not completely clear, but the published Silmarillion places it chronologically after Beren's loss of his hand and before Beren's return to Menegroth. Taken literally, this would date Daeron's loss as I 466.

The meaning of the 'East' in this context is not explained in any detail, but it must at least mean that Daeron wandered over the Blue Mountains into Eriador (which at that time was an untamed wilderness). There is no record of Daeron being encountered in later ages, so we can perhaps presume that he wandered farther eastward still, ultimately vanishing into the distant and unknown lands of Rhûn.

Daeron's name seems to be connected to a dair, a word from the Doriathrin dialect meaning 'shadow of trees' (according to The Etymologies in volume V of The History of Middle-earth). That word is specifically connected to the name Dairon (the older spelling of Daeron), so Daeron's name seems to mean something like 'of the tree shadows'. This would make sense for a character who secretly spied upon Beren and Lúthien from beneath the shadowed boughs of the forests of Doriath.