Admiral Geir Gulbrand was the commanding officer of the UNSC 30th Fleet (2539- ). Geir led his fleet to multiple engagements over the following ten years, securing badly needed victories for the Navy in humanity's growing desperation toward the end of the war. The fleet's most renowned engagement occurred when they arrived in the Hyacinth system late in 2551 after communications with Jacinto were lost when the main Covenant force invaded, providing assistance and reinforcements to the besieged Jacintans on the surface. Following the death of Admiral Vincent Clare of the Hyacinth defence fleet, Gulbrand became the supreme commander for all UNSC forces for the duration of the Siege of Jacinto.