Move the slider to any year: every polity recorded for that year is drawn. Bulgarian states are gold; the Thracian kingdoms and the other powers that ruled the Bulgarian lands in the current chapter are green, and everything else is grey; 42 chapters carry the story. Borders change only where the dataset records a change, and they fade rather than morph between dated polygons. The slider is stretched so that the dense modern centuries get more room than the long ancient ones. Stars mark capitals and dots mark sites, each shown in its own years. Hover a territory for its name and dates; click it to open its Wikipedia article.

Boundaries are approximate reconstructions, and ancient and early medieval dates are approximate. The dataset has no state borders before about 750 BCE, so the first chapter shows only the sites of the Varna culture. Cliopatria’s “Principality of Bulgaria” is labelled “Tsardom of Bulgaria” from 1908, Eastern Rumelia (1879–1885) is derived from the dataset, and San Stefano Bulgaria (1878) is a hand-drawn, approximate outline of the borders proposed by the treaty. The dashed line is modern Bulgaria, for orientation only.