Finwë SlainFinwë Slain (4995 F.A.) - Manwë held a great festival in an attempt to heal the rift between the Valar and the Noldor (this was the same festival at which Melkor and Ungoliant destroyed the two Trees).  Fëanor attended, but Finwë remained exiled in Formenos.  After the Trees perished, Valinor was plunged into darkness.  Melkor was not yet finished with his plan.  With the world dark, he could travel freely without fear of being caught.  So he went north to Formenos to obtain that which he coveted most.


"But Melkor also was there, and he came to the house of Fëanor, and there he slew Finwë King of the Noldor before his doors, and spilled the first blood in the Blessed Realm; for Finwë alone had not fled the horror of the Dark.  And they told that Melkor had broken the stronghold of Formenos, and taken all the jewels of the Noldor that were hoarded in that place; and the Silmarils were gone...Then Fëanor rose, and lifting up his hand before Manwë he cursed Melkor, naming him Morgoth, the Black Foe of the World." ~The Simarillion, chap. 9 (Of the flight of the Noldor)


Now Morgoth had the Silmarils, so he fled Aman altogether and returned to his fortress at Angband.