Siricius was unanimously elected to the Papacy in 384 and he is widely regarded as the first Pope to be called……well….Pope. Now this doesn’t mean that there were not Popes before him,as some Protestants would claim,it just means that the leader of our Church wasn’t always called Pope.He also didn’t always wear a big hat either.The word Pope is from the Latin word Papa,which means Father,and lest anyone question that the Pope was in charge,Siricius is also the first Pope to use the title PONTIFEX MAXIMUS,which basically means he’s the chief priest of the Christian world. You don’t have to use all caps when typing PONTIFEX MAXIMUS,but it just feels like it needs all capital letters. PONTIFE….sorry…..Pope Siricius is the first Pope to issue something called decretals. A decretal is a official statement to a question that someone may need an answer to,like “Hey Pope,if I’m a priest,can I get married?”,and he would reply “Eh,I wouldn’t encourage that,so that’s a no” and he would probably sign it PONTIFEX MAXIMUS. In all caps.