It is said that the devil has many names. While he is commonly known as Satan, there are those who claim he’s a fallen angel named Lucifer (though a number of people think this is a translation error), a Great Red Dragon or even a Beast embazoned with the Number 666. There are also some who refer to the devil by the name Azazel (a figure like the titan Prometheus in Jewish myth), or who call him Beelzebub, the Lord of the Flies. This last title, like many of the others people use, is actually an interesting result of time, culture and a duel of religions in the Middle East during biblical times.
First, what the book says. Beelzebub, or Baalzebub as it was spelled in older versions, is translated roughly to the Lord of the Flies. It is said that he is a powerful devil that is high up in the echelons of hell, but that Beelzebub is not Satan. According to the Testament of King Solomon (the same one who set out sexual rules of the Abrahamic faith), Beelzebub is a devil that creates lusts in priests, rules with tyrants and causes men to worship devils and demons rather than to worship god. A great player of politics, Beelzebub was also supposed to be an instigator of wars and corrupter of leaders.
Let us dig back past all of the demonology though and look at the name of this being. Names have power, and this is why what you call something can mean a lot in any religion, Christianity included. “Beelzebub” was spelled “Baalzebub” in older versions. Because the name is actually two pieces. It was originally a reference to “Baal-Zebul” which is a title that means roughly “Prince Baal.” The mocking version of this title was “Baal-Zevuv,” essentially stripping the god Baal of the princely (or in this case godly) title.
Dig back a little bit further. Baal, or Ba’al as it definitely has two syllables, was a god of sun and storms in the ancient Middle East. Baal was worshiped by the Philistines (where he had a prophet at the city of Ekron or Accaron), the Canaanites, Phoenicians and many other ancient peoples. Though the mythology was complex, Baal was a sun god who died and was resurrected in his triumph over death, a story that many pagan gods associated with the seasons all over the world share. Baal was mighty, the son of the chief god El, and he had power of droughts and sun, storms and rain, which were essentially the everyday things that could make or break farmers in the ancient times.
In fact, Baal was not unknown to the Semitic peoples (the people who came after Noah and who worshiped Yaweh). His worship extended into these old communities, and though Yaweh was put at the pinnacle of divine worship, it was Baal who was appealed to for daily needs and given much sacrifice to. Yaweh, seen as the ultimate power, was considered too important to pray to for minor things, so the people would offer sacrifice ranging from crops and burnt offerings to sex to humans (though the last only in case of emergency) to capture the interest and favor of Baal. This is a practice not unlike how modern Catholics might appeal to the archangel Michael or to Saint Brigid rather than praying directly to Jesus for assistance. Lesser entities are seen as closer to Earth, and therefore more able to help you. Kind of like going to middle management before demanding that the CEO see to your problem.
Because the worship of Baal was so widespread (the Phoenicians especially brought the word of the religion in their travels since they were master ship builders) it seemed that everyone from the Israelites to isolated desert tribes had heard of the god. While the religious classes of Israel often tried to curb the worship of Baal, the practice was never fully stamped out. In fact even today you can find altars and buildings depicting the image of the storm god. The last move was to demonize the god, a practice famously used to convert pagans to Christianity by figures like Saint Patrick. You simply take a popular divine figure and turn that figure into a demon or devil (hence the idea of a powerful, wicked being the Lord of the Flies) in order to make the point that this figure that you looked to for guidance is in fact evil, and leading you astray from the proper path.
This impression obviously stuck, judging from how rarely Baal is mentioned as a divine being and how often he’s mentioned as an agent of evil in biblical text. Perhaps the most obvious section about this is when Jesus was casting out demons in the New Testament. Others who doubted him tried to discredit Jesus by saying that he himself was possessed by a greater devil, Beelzebub, and thus he had power over lesser demons. This of course lead to the speech about how a house divided cannot stand, and pointing out how nonsensical it would be for a force of Satan to go against a force of Satan. Of course there have been other mentions of Beelzebub in popular culture, ranging from Milton’s “Paradise Lost” up to stories by Edgar Allen Poe and others who used the name of demons to inspire horror and dread. Even video games use some of these names, such as the popular “Diablo” franchise making Baal one of the most powerful lords of hell. Some things never change is seems, which is what happens when you lose important pieces of history.
“Baal,” by Alan G. Hefner at Pantheon
“Ba’al Worship in the Old Testament,” by Dennis Bratcher at Cri Voice
“Beelzebub,” by Anonymous at New Advent