F.A. 543-544: Preparations
Preparations in Valinor for the War of Wrath against Morgoth and the rescue of the peoples of Beleriand. The army as a whole is led by Eönwë, the herald of Manwë; it includes Valar (ambiguously), Maiar, the Vanyar, and the Valinorean Noldor led by Finarfin. Few of the Teleri are willing to go to the war, because of the Kinslaying; but at the request of Elwing, who is kin to them, they send mariners to man the ships to carry the Valinorean Elven armies over the water.
Optional Readings
If you want to read the parts of The Silmarillion covering the events described in this post, they are found in the following chapters:
Chapter 24, “Of the Voyage of Eärendil and the War of Wrath,” paragraph 22 (being “Yet it is said that Morgoth looked not for the assault that came upon him from the West…”.).