The Hermeticization of the Slavic Lands followed very quickly on the Christianization of Kievan Rus under Vladimir the Great in 988.

Three covenants were founded in quick succession in the years 992-994 AD.
  1. Rodnya south of Kiev, founded by Thebes;
  2. Pripet Maior founded by Transylvania in the Pripet Marshes; and
  3. Grand Silesia founded by the Rhine in Poland.

These initial settlements were clear competition for resources and attempts to extend the influence and power of their respective tribunals.  This accompanied the general breakdown in Order relations that preceded the Schism War.

The ploy broke down when Rodnya, the Theban plant was ordered to assist in a strike on a Transylvanian covenant in 1003.  This blatantly illegal move spurred a bit of introspection first at Rodnya, where it was led by the Guernicus magus, Patrick of Dunderry.  After he refused the order, he inadvertently launched a movement that spread through all three covenants, who increasingly recognized the fact that their common similarities might be more important than their rivalries and their allegiances to the Western tribunals.

This eventually led to the formal declaration, in 1008, of the New Slavonic Tribunal.  In order to legitimate a quorum (which required three magi from each of 4 covenants), each of three true founding members "contributed" one magus to found the covenant of  Nova Slavonica near Polotsk.  It was a fairly blatant attempt to get around Hermetic law, but in the era of the Schism it (barely) passed legal muster.

Retribution was quick; the covenants of Rodnya and Grand Silesia were both struck in 1009 by Western magi in punitive (but covert) attacks.  Rodnya was so badly compromised that the magi abandoned the site and relocated north to the site of Three Lakes (Tres Lacus), where they re-founded their covenant in 1010.  Silesia was temporarily abandoned as the magi fled to Pripet, but it was resettled in 1013 while the Westerners were distracted by the Schism War.

Although there were some raids, the Schism War was more peaceful in the East than the West - in the whole Tribunal, there had been only one Diedne, who was among the original founders of Pripet Maior. He was quietly slain after the declaration of war. As a result, although Slavonic magi participated in the war, honoring commitments and sating rivalries they had cultivated in the West, few battles were fought on their home turf.

In the various tribunals and meetings that concluded the war, ratification of the independence of New Slavonic was secured, over the objections of the Rhine, Transylvanian and Theban voters.  (The farce of having a tribunal with only about 20 magi was quietly overlooked.)

For 20 years, the covenants grew in relative peace, but disaster struck in 1039, when the covenant of Grand Silesia was destroyed by the Poles. (Treasonous assistance by agents of the Rhine Tribunal is still to this day suspected but unproven.) The three survivors of the assault relocated to Pripet Maior. Two years later, Nova Slavonica also fell to, and all its mages were slain by, an unknown faerie assailant.  This left the tribunal, still only 33 years old, with only two covenants, thirteen members, and in serious danger of being declared inquorate and dissolved into its various rivals.

Magi in the Rhine, Transylvania and Thebes began to make covert plans for carving up the New Slavonic at the next Grand Tribunal (1063.)  Some also began to prepare new expeditionary foundations within Slavonic territory, in order to reassert their interests in the region.  In order to forestall this, the Tribunal declared, at an emergency meeting in 1043, (again playing some games with temporary covenants to skirt the legal issues),

The legality of these unprecedented measures is certain to be reviewed by the Grand Tribunal in 1063, but until then they have the force of law.  The hope on the part of the locals is that these four new Covenants will strengthen the numbers and legitimacy of the New Slavonic Tribunal, that at least two of them will survive until the next Grand Tribunal in 1063 to ratify its continued existence, and (crucially) that they will help define the borders of the Tribunal against encroachment.  This last goal helps explain the placement of these new covenants - one (New Silesia) in western Poland, one (Alba Lendia) on the northern edge of the Carpathians, and one (Magna Borysthenia) in the south along the Dnieper, near the edge of Slavic territory.  (The fourth, Neroniana, is further east, on the shores of Lake Nero, to bolster the eastern presence alongside Tres Lacus.)