Durin was the first of the creations of Aulë to awaken in the very first days.  A note on the naming of dwarves.

• 03.044 with the last light of Durin’s Day
• 03.045 “Durin, Durin!” said Thorin.
• 03.045 “Durin, Durin!” said Thorin.
• 03.046 “Then what is Durin’s Day?”
• 03.047 We still call it Durin’s Day
• 04.003 “and perhaps it will be Durin’s Day”
• 10.008 Thror and Thrain of the race of Durin,
• 10.023 and Kili of the race of Durin,
• 15.020 of the great folk of Durin
• 17.015 By the beard of Durin!