Borders dataset for year . Borders are based on Historical Basemaps by Andrei Ourednik et al., licensed under CC-BY 4.0. Borders for medieval and early-modern periods are scholarly approximations — political reality on the ground was often messier than any line on a map can show. Ruler and era data is drawn from the Rulers page and Project White Eagle research. Press F for fullscreen, I to toggle the era panel, Esc to exit fullscreen, ← → to scrub.