From the mission and crusade in Livonia around 1200 to the final suppression of Prussian resistance in the 1270s and 1280s, the Baltic crusades conquered the last pagan peoples of the southern and eastern Baltic and replaced their societies with a monastic state. Henry of Livonia's chronicle and Peter of Dusburg's Chronicon terrae Prussiae, both written from inside the enterprise, record campaigns of devastation, the killing and enslavement of populations, forced baptism and the razing of strongholds; the Great Prussian Uprising of 1260–1274 and its suppression were especially destructive. Conquest was followed by systematic colonisation: German and Polish settlers were brought in under charter, towns were founded, and the surviving Prussian population was reduced to a subordinate rural stratum whose language died out by about 1700. No population figures survive from the conquest itself, and modern estimates of the pre-conquest Prussian population and of losses are extrapolations from later records.
The Sword Brothers and then the Teutonic Order, with crusader contingents and German and Polish settlers, conquered the pagan Livs, Estonians, Latgalians and Old Prussians and built a monastic state over their lands
No records exist for the pre-conquest period; estimates come from archaeological settlement surveys and back-projection from the Order's own later land registers. Henryk Lowmianski's reconstruction gives Prussia roughly 170,000-200,000, and the Livonian lands - Estonians, Latgalians, Livs, Curonians, Semigallians - are put at 250,000-350,000. The full plausible range is about 350,000-600,000.
No usable figures. Peter of Dusburg and Henry of Livonia describe killings, enslavement and the devastation of whole districts across nearly a century of intermittent war, but neither they nor any later source supplies totals, and no modern reconstruction attempts one.
Killings, the burning of settlements and the enslavement of captives are documented by Henry of Livonia's chronicle and Peter of Dusburg's Chronicon terrae Prussiae, both written from within the crusading enterprise.
Poland, Germany, Russia