Polans and other Polish tribes came to the territory of today's Poland, probably in the VIII and IX century, bringing their beliefs on the west. Polans and their beliefs describes the Primary Chronicle wrote by Ruthenian chronicler Nestor. There are also famous Helmold's Chronica Slavorum and the other chronicles and notes of German bishops, geographs, as well as the old Ruthenian chroniclers and Jewish or Arabian traders of Slavs. The history of paganism as the main religion in Poland ends Baptism of Poland in 966, but it is not end of Slavic paganism in this country at all. Pagans would not agree to Christian reforms of Mieszko I and his sons, causing a Pagan Reaction in Poland that culminated in uprising of pagans in 1037-1038 (later supressed by Casimir the Restorer). During the uprising, pagans killed priests and destroyed churches.The end of the uprising was not the end of paganism in Poland. Pagans lived in Poland even to the XII century, when last pagans were Christianised in West Pomerania by bishop Otto from Bamberg and Boleslav III Wrymouth.