Frederick Barbarossa was elected King of Germany in 1152 and crowned Holy Roman Emperor in 1155. Shortly thereafter, an apparent misunderstanding with Pope Adrian IV led Frederick to mount military operations against Italy and install an antipope in opposition to Adrian’s successor. The schism continued for some time, but Frederick and the Catholic pontiff ultimately reconciled. According to scholars, what factors may have contributed to Frederick’s drowning death in the shallow Saleph River? Discuss