Osnabi campaigns
The Osnabi campaigns were a pair of wars of expansion and settlement initiated by the emperor Rusuro Tirumfegla from 312-320 IE and 325-328 IE. Seeking to distinguish the Tirumfegla dynasty, Rusuro's expansion into what is now the Ashnabis Territory had three prongs: to the north, out of the Choradani city of Kindi Nasku, to the center, from the city of Kebulund, and from the south, from the Umnakan city of Jinto. While not impassable, the Filija Mountains that had long marked the western boundary of the Omban Empire proved a real challenge for the Omban armies, despite the presence of large contingents of bubun soldiers.
The first Osnabi campaign was most successful in the northeastern part of Ashnabis, where Omban settlements along the coast were rapidly established. Progress in the south and center was much less successful militarily, but Rusuro encouraged new settlements of Ombesh speakers throughout the plains west of the mountains, and these footholds would prove vital for the second campaign. The area designated as Osnabis by the emperor was a massive one, larger than any of the existing Omban provinces, highly cross-culturally diverse and politically varied. The challenge of managing these different sorts of complex military and political goals eventually led the military expansion to fizzle, other than setting up some forts to support the new settlers.
The second Osnabi campaign, beginning in 325, was a massive and concerted military expedition into the heart of Osnabis and through to the western coast. Though much shorter in duration, its impact was felt much more strongly, as it expanded at least by a factor of three the number of Omban colonists in the area, and was accompanied by a major project of religious conversion. Despite the relative success of the campaign, it came to an end in 328, unfinished, as Imperial finances were already under strain. Other than a small area that was appended to northwestern Choradan, there was no permanent extension of the borders of the Empire. In fact, it is now largely judged that the economic strain of the Osnabi campaigns was a major contributing factor to the end of the empire in 338.
