September 23, 1122 - Pope Callistus II and Emperor Henry V Agree

The Concordant of Worms (which is not an arthropod convention) is held in Worms (now Germany) where the Holy Roman Emperor Henry V acquiesces to Pope Callixtus II and agrees to get out of church business.  Many of the Holy Roman Emperors prior to Henry used their influence to choose bishops and determine how the church was run within the Empire.  Things came to head when Pope Callistus II pushed back, Henry confiscated church lands/property and there was a big mess until they came to an agreement on September 23, 1122.