Treaty of Highwind
The Treaty of Highwind was a major treaty signed by the Air Nation and the Earth Kingdom, which established an alliance between the two nations and effectively pacified the Northern Sea indefinitely. As well as ending the longstanding rivalry between the nations, other components were also significant. The treaty established a student exchange program between the University of Ba Sing Se and the Institute for Empyrean Studies, conceded the right of Air Nationals to practise Empyreanism in private while within Earth Kingdom borders, and established extradition rights.
The Treaty of Highwind was notable for being built on the foundations laid by the prior Treaty of Gaoling, which had pacified most of the Northern Sea already. In particular, the new treaty established that the two powers would work jointly "to take the necessary steps to preserve peace and security" if "aggression by a third party" were to occur. While this has never been tested, due to an absence of pirates or other hostile powers, the nation of Albion may put this condition to the test.
The Western Protectorate, fully demilitarised in the Treaty of Gaoling, was able to accept organised settlers following the Treaty of Highwind's ratification, with all risk of threat by sea removed and the likelihood of raids from the Khanate low. This led to the creation of Whitewood, an Elysian Empyrean community. Another Empyrean community was also formed out of revulsion at the treaty, with the Sovereign Order organising as a radical offshoot of Northern Empyrean theology that rejected the notion of allying with earthbenders for religious reasons. The Order would leave the Air Nation to settle in Eldhavet, referring to themselves as the Ultramar Temple.