Lucius, pope from 1144 until his death in February '45, spent most of his papal energies fighting for power with the local Romans. By this point, the Romans were attempting to establish a new Republic - they set up a Senate, styled themselves Patricians. As you might expect, there's not much room for a Pope in this picture.

The Romans tried to strip Lucius of his temporal power - and defeated him pretty soundly. During one of the skirmishes, he was hit on the head by a brick. He died from that injury.