St. Leo III was a different kind of pope than his predecessor, Adrian I. He wasn’t a part of the Roman nobility, which made him a hostile target of theirs from the moment of his election, two days after Christmas in 795. Prior to his election, Leo was a cardinal serving at the church of St. Susanna in Rome. To ward off the Saracen army, who seemed to enjoy raiding cities from the sea, Charlemagne advised Leo III to learn to play Battleship and establish a navy to patrol the Italian coastline.

Large sums of money provided to the Church by Charlemagne allowed Leo III to give generously to the poor and renovate churches in both Rome and Ravenna. Leo III, also a patron of the arts, appeared to particularly love mosaics, having commissioned a piece portraying his relationship with the king and preferring the style when decorating churches. He died June 12, 816, but wasn’t canonized a saint until 1673, by Pope Clement X.

St. Leo III effectively ushered in what’s become known as the “Holy Roman Empire.” After being kidnapped by Roman aristocrats, then saved by Charlemagne late in the 8th Century, Leo III crowned the Frankish king the first Holy Roman Emperor on Christmas Day in the year 800. His kingdom now held power over the majority of western Europe, nearly all of which was a part of Christendom as well, so it was a move that made sense. The coronation had many benefits, but was nevertheless a tad controversial.

Charlemagne’s post allowed him to gather the best scholars from across the Christian world to form schools, transcribe and preserve ancient documents, and to advance efforts in architecture, technology, and agriculture. The iron horseshoe, a padded harness for horses while plowing, and triple crop rotation were all products of this period of Charlemagne’s rule. The controversies, however, included the filioque (“..and the son” in the Nicene Creed) issue being reignited amidst already-tense East-West relations, and Charlemagne’s temptation to believe that his position allowed him to comment on doctrine from time to time.

Fun fact: After his death, Leo III’s relics were entombed with the first two Popes Leo in St. Peter’s Basilica. The relics of Leo IV joined the trio in 855 and the four remained there for 1000 years, until St. Leo the Great’s relics were removed and placed in their own chapel.

In the year 810, the famous Book of Kells, an illuminated manuscript of the Gospels and other texts, was completed in a Columban monastery in Ireland.  The book has been on display in the Old Library at Trinity College in Dublin since the mid-19th Century.