A straightforward explanation of what the Palantíri are and their history across the ages. One part of the rough draft that didn’t make it into the final video was speculation as to the two most probable explanations as to how the Palantíri went from Aman in the First Age to Tol Eressëa in the Second:
We know nothing of the history of the palantíri after their forging before the First Age for many millennia, though we might hazard some guesses. One possibility is that the Noldor produced a plethora of palantíri, eight or more of which were gifted to the Elves indigenous to Tol Eressëa, and that it was from them that the Númenoreans received the Seven Stones. But far more likely is that the Stones had been in the possession of the Noldor. When the Exiles forsook Aman, they would have taken all the treasures they possessed instead of leaving such behind, including their palantíri. These would have been brought to Beleriand, though there appears no record of them playing any part of the events of the First Age. Any Stones that survived the War of Wrath and the sinking of Beleriand would have been brought back to Tol Eressëa by those Elves who went West at the end of the Age. From these Elven immigrants to Tol Eressëa, who had an already established friendship with Men in Beleriand, would have come the Seven.
The Hub City Review 