The father of all dragons, he appears for the first time between the second and third battle of Beleriand some 260 years after the raising of the Sun and Moon. Glaurung was a hot Dragon without wings.
F.A.260. Glaurung issued forth for the first time. He came from the gates of Angband by night; he was scarcely half-grown but the Elves fled in fear before him to Dorthonion and Ered Wethrin. Fingon rode against him with archers upon horseback, and encircled him with a ring of swift riders. Glaurung was dismayed for he could not endure their darts, having not yet developed his full armor, so he fled back to Angband.
F.A.495. Glaurung sacked Nargothrond this year. He came from Angband with a host of Orcs into Hithlum and did great evil. He came over the mountains of Ered Wethrin and down at the other side, destroyed the Pools of Ivrin and came into the realm of Narog.
Meanwhile, Túrin had persuaded the Elves to abandon their stealth / ambush strategy against Morgoth for open war and this allowed Morgoth to discover Nargothrond. Thus Glaurung found the caves of Nargothrond. In the battle of Tum Halad, Glaurung defeated the Elves and entered Nargothrond victorious and took possession of the treasures and the Nauglamír there.
F.A.496. Morwen and Nienor came with a small host of Elves commanded by Mablung out of Doriath to seek Túrin. Instead they met Glaurung who bewitched Nienor and she ran lost into the wood. Morwen escaped Glaurung but was also lost. Mablung returned to Doriath.
F.A.499. Glaurung attacked Brethil but was slain by Túrin.
Related Links.: Battles.: Battle of Tum Halad. Encyc.: Glaurung.