The moment
On Christmas Day 800 Pope Leo III crowned the Frankish king Charles as emperor in St Peter's; his biographer Einhard claimed that Charles would never have entered the church that day had he known the pope's plan. Charles had spent three decades subduing the pagan Saxons and forcing them to accept baptism: his law for Saxony made refusing it a capital offence, and in 782 he had 4,500 Saxon captives executed at Verden, as the royal annals record.
People: Charlemagne, Pope Leo III, Alcuin of York, Einhard