The outpost of Àirde was originally held by a lesser House of The Caorrani, vassals of a long forgotten county, with Deargailbh as the capital. During a large battle, the heirless Lord of Àirde was murdered by his wife before she commited suicide, thus ending the bloodline. Ewan Cousland, captain of Àirde's guard, took the lands and title, forming the Cadet Branch House Cousland of The Caorrani, which wasn't recognized until much later.
The Couslands then declared their independence from that county, starting a war that lasted around 50 years. When the war finally ended thanks to a peace treaty brokered by Cailean Cousland's forefathers, Àirde won its independence and possession of half the land that had once been southeastern Deargailbh and recognition from the ruler of Caorran as independent from their former suzerain and House Cousland was officialy created.
A few years later, Lachlann Cousland became the First Custodian of The Grey Custodians and took control over Deargailbh. He then pledged his loyalty to Àirde, held by his brother Cailean Cousland, which led to the creation of Gallaran, uniting the towns of Deargailbh and Àirde once more. As First Custodian and Lord of Deargailbh, Lachlann Cousland's first step was to create a Barony held directly by the Order of The Caorrani Custodians.
Under Cailean Cousland, Gallaran has since expanded towards the North, reaching Luthadriel and the Western Confederation, annexing Ultramar and Ipê-amarelo in the process. He also diplomatically annexed the insular realm of Kaitain, which was split between Eileaniar and Eileaniòn, gaining new lands with metal deposits and fertile fields, placing Gallaran as one of the strongest subrealms of Caorran.