First Battle of Beleriand
While the Noldor still toiled through Araman, Morgoth had already arrived in Middle-earth, and had occupied his old fortress of Angband where his servants Sauron and Gothmog had long been breeding Orcs.
Unexpected by the Sindar, Morgoth decided to try and secure the area quickly, and he sent out his armies. This was the only battle against the Dark Lord that the Sindar took an active role. Morgoth's forces broke into two hosts, passing west through the vale of Sirion and east between Aros and Gelion, some of them even scaling the passes of Anarch and Aglon.
In the east, King Elu Thingol of Doriath took the offense, meeting the Orcs at Amon Ereb. There King Denethor of the Laiquendi met him, and the Orcs were forced back-to-back. The lightly armed company of Denethor fell on Amon Ereb before Thingol could rescue him and King Denethor himself was slain, but the Orcs were eventually defeated. Those few survivors were slain by the Dwarves of Mount Dolmed.
In the west, the Elves of the Falas under their Lord Círdan attacked the western host, but they lost that fight, and retreated in their cities of Eglarest and Brithombar. These cities were besieged afterwards, and Doriath was unable to gather a strong enough force to send aid. The Havens were only freed when the Orcs withdrew to fight the Noldor under Fëanor.
After the First Battle Doriath was protected by the magical Girdle of Melian.
The death of King Denethor in this battle led the Laiquendi to pledge to never again name a king or participate in the wars between the other Elves and Morgoth.