Gloin (glo-in), father of Gimli and sixth companion of Bilbo and Gandalf in their journey to reclaim the Lonely Mountain, was born in 2783 of the Third Age. He had an older brother in his family named Oin. The Gloin brothers were extremely valuable to the Quest of Erebor (the Lonely Mountain) because they were highly adept at making fires. He, like the other most famous Dwarves, was of the Longbeard clan (Durin's Folk), and like his son he was also of the Lonely Mountain Dwarves. In 2799, after the Battle of Azanulbizar, he accompanied Thorin Oakenshield to the Blue Mountains to set up a new home. Gimli, the son of Gloin, was born in 2879.
In 2941, he went with twelve other Dwarves and with Gandalf to Bilbo's house to recruit Bilbo to their cause. Gloin differed from the other Longbeards in that he saw Bilbo as "a grocer" and not as a burglar. However, the more Bilbo contributed to the Quest of Erebor, the more respect Gloin gained for Bilbo, and eventually the two of them became friends.
After the Battle of the Five Armies, Gloin remained at the Lonely Mountain, where all of the Dwarves regained their former prosperity. Gloin had lost a family member when Balin had lead a Dwarven army to Moria to re-establish Khazad Dum, the former Misty Mountains-based Dwarven kingdom, failing to do so. Then, in 3017, a messanger of Mordor came to Erebor asking for information about Bilbo and the One Ring. Gloin and Gimli traveled to Rivendell to warn Bilbo about the new threat and to seek advice from Elrond. While doing so, they met Bilbo's nephew, Frodo Baggins. Both Gloin and his son, Gimli, attended the Council of Elrond, in which Gimli was appointed to be the Dwarven race's representative in the Fellowship.
Sources:
Encyclopedia of Arda entry on Gloin
Thain's Book entry on Gloin
