Various Slavic tribes entered the region of modern Polsta on the heels of the Goths fleeing the Huns in the 12th century. The Polanian Slavs, which would eventually come make the core of the Polish state settled between the Rivers Varta (Warta) and Vistula. When Attila was killed in 1207(454) the Hun Empire quickly fragmented. The Polanians seceded from it in 1209(456) and would remain one of many tribes in non-Roman Europe, uniting in confederation at times of Roman hostility. The Slavs would adopt many Roman military practices, but largely very little would occur politically in west-central Europe for five hundred years.
Poliski created a strong religion centred on his family being of divine origin and had many temples built where his divine family was worshipped. Pomp and circumstance fed the peoples' adherence to this new religion at a time when the old paganisms were becoming stale, though the pagans would not disappear. Poliski would rule until his death in 1735(982) where his eldest son Erlstaw succeeded him.
Erlstaw strengthened Polescijanstow (the religion) to bring the concept that the state of Polsta itself was a holy entity to be worshipped and maintained. He decried pagan religions and began persecuting them, to the dismay of Prusenia, Lietuvia, and surrounding tribes. Erlstaw modified the structure of Polescijanstow, elevating his father to creator of the world (not that all that much of the wider world was known by the people) and himself Earth-King (Telektrkzol) To Rejoin His Holy Father In Passing, and setting the role of successors as The Succeeding Spirit of the Earth-King. This basically made it that every Telektrkzol sort of went in both directions when he died, both rejoining the God-King Poliski, and uniting with the new Earth-King as the Succeeding Spirit; which required a very large ceremony (make togue sticking out emoticon here). Erlstaw began a new year system as well in 1736(983), rejecting the commonly used AUC. It was based supposedly on the age of the Earth, which his "astronomers" "calculated" to be three thousand one hundred and sixty-five (3165) years prior, dates in this article will still be in AUC (CE). All these changes and demands created an undercurrent of discontent and friction in Polsta.
Upon the birth of Erlstaw's son in 1740(987) (he had had a daughter born in 1737(984), but she had been immediately euthanised as required by the Divine Laws of Succession), Erlstaw became Earlstaw I and his son II. E.I. would rule until his death at the age of 73 in 1774(1021).
Erlstaw II & III
E.II. and III would spend much of their reigns (1774(1021)-1813(1059)) expanding Polsta, solidifying the Polescijanstow institution, and fighting neighbours variously due to religious and territorial claims; also stopping the final Roman attempt at further European expansion in 1795(1042).
Death of the Earth-King
By 1809(1056) the kingdom was a steadily growing political and economic entity. Unlike most Slavic and Baltic nations or tribes however, Polsta actually expanded its trade relations with Kiev as Kiev descended into anarchy, and with its collapse in 1812(1059) Polsta's economy began failing. A rebellion of tribes in the west, instigated by Rome, required that Earth-King Erlstaw III personally lead a large force to suppress it and restore awe to the state, but he was felled at the Battle of Laudenczin Castle (~Szczecinek) on Maius 25th 1813(1060). Erstaw III was 51 at the time and in his 14th year of rule. His son Erstaw IV was only six (and his other son, Zahkarn three), too young to be allowed the ceremony of the Succeeding Spirit, but that aside, the death of Erstaw III at the hands of rebels was a catastrophic blow to the legitimacy of Polescijanstow and the Poliski Dynasty. The rebels kept the body of the dead Earth-King which also prevented the ceremony from being performed anyways. A power struggle began between the clerics in Angsiglcin, resulting in the murder of Erstaw IV in Junius and Zahkarn being renamed Estaw V while the clerics ruled and fought amongst themselves.
While this was going on, the rebels, made up of both pagans and Polescijanstin, began fighting each other in Junius as well when their main leader, a pagan named Cezar Gowel, denounced Polescijanstow as a sham and vowed to wipe it from Polsta. During the violent infighting Gowel apparently had a communion with the hastily embalmed Estaw III. Gowel emerged from the palace at Laudenczin and halted the fighting in the streets with his proclamation that the Earth-King Spirit had joined with him, one which was not a member of the Poliski Dynasty and a practicing pagan. Convincing all present, Gowel named himself Telektroczynika (Earth-Regent) and announced that Polescijanstow had been poorly followed and warped by the establishment in Angsiglcin. This religious revolution swept up the rebels and gained new followers throughout the west. Gowel, now referring to himself only as Telektroczynika, set Polsta's new capital as Poznan with a theocratic oligarchy with a new clerical bureaucracy, and marched east. He and his followers defeated the old cleric government operating from Angsiglcin and in 1816(1063) Polsta was again united. Gowel became head of the oligarchy, though in theory all clerics of the oligarchy were equal. The new Polescijanstow was far more tolerant, Estaw V was made a figurehead of the state, and Polsta was able to live more peacefully with its neighbours, but the people still saw themselves as the defenders against Rome, and raids would continue into the next century.
Kingdom to Republic
In 1989(1236) Polsta drew up a new constitution changing it from a theocratic kingdom to a constitutional republic. Polescijanstow was still a majority religion in Polsta and had some adherents in surrounding regions.