🔼The name Legion in the Bible
The name Legion occurs twice in the Bible, but in one context. Both Mark and Luke tell the harrowing story of a demon possessed man who wandered the tombs of the Gerasenes, continuously crying out and cutting himself with stones (Matthew tells the same story but with two unnamed men; Matthew 8:28-34). When he sees Jesus he identifies Him as the Son of the Most High God. When Jesus asks the man to say his name, he says, "My name is Legion because we are many" (Mark 5:9, Luke 8:30).
Jesus famously sends the demonic legion into the herd of swine, which promptly destroys itself. Mark uses the word λεγεων (legeon), legion, one more time as he speaks of the man who had had the legion (Mark 5:15).
🔼A little background
The story of the man named Legion has rightly puzzled readers for centuries. A little background info might lift the clouds somewhat:
The designation legion as a Roman military unit came about during the Marian reforms of 107 BC. A legion would contain around 4,500 to 5,500 legionaries (professional soldiers who were Roman citizens), divided into cohorts (480 legionaries) and cohorts consisted of centuries (80 legionaries). But the army at large consisted mainly of auxiliary cohorts (which in turn consisted of non-Roman citizens), and every Roman legion always came with a hardy helping of foreign cohorts.
By stating that his name is Legion, the demoniac is being quite specific. In modern English we like to use the word legion to indicate a myriad, but that's not what the word legion meant to the people of the first century AD (see etymology below). Back in the day, the word legion was a Roman-specific term, much like "SS" was to the Nazis or "Stasi" was to East Germany. By using the word legion (in stead of calling himself, say, Ten Cohorts) the demoniac makes a point to indicate that his demonic infection consists of "Roman citizens".
🔼The Battle of Beth-horon
By the time the gospels began to circulate, the word legion had another specific meaning. In 66 AD, Jewish rebels destroyed Julius Caesar's legendary Legion XII Fulminata at the battle of Beth-horon (means House of Caverns; the tombs of the Gerasenes were doubtlessly rock-hewn sepulchres. Also see the "other" battle of Beth-horon described in Joshua 10:11). The number of casualties isn't the same but the shock value and effects of the defeat of Legion XII can be readily compared to the destruction of Custer's 7th cavalry at Little Bighorn.
Upon hearing the news, Emperor Nero personally sent general Vespasian and his son Titus to Judea to settle things and a bloody invasion of Galilee ensued. Nero soon killed himself and Vespasian became emperor. Titus marched on Jerusalem and sacked it in 70 AD. The temple was raised to the ground. Titus succeeded his father as emperor of Rome.
Since the fulfilment of prophecy is a major theme of the gospels, the scene of the man named Legion was doubtlessly recognized by some to be a prophecy of the battle of Beth-horon. And since the destruction of the temple was initially viewed as the greatest disaster possible, it was diligently explained by Christians to be quite beneficial for people's understanding of the relationship between God and man. Vespasian's nickname was Mule, which made Titus a Mule's Foal. The same people who recognized the battle of Beth-horon in the story of the man named Legion probably also had certain associations with the story of the Triumphal Entry (Matthew 21:5, Zechariah 9:9).
🔼Legions' Number and Name
One of many curious details of the story of the man named Legion is that Roman legions were designated by a serial number and commonly came with a name. The name was handy because emperors liked to start counting from One, which led to many legions with the same number. During the republic years, there were 28 original Augustinian legions and the highest number given to an active legion (that we know of) was Thirty. There was one Legion Thirty in Julius' Caesar's days (named Classica), and one levied by Trajan in 100 AD (named Ulpia Victrix).
The demoniac stating that his name was Legion may have led a first century reader to wonder what this Legion's numerical and cognominal designations might be.
By being vague about the cognominal designation of his legion's name, the demoniac also brings to mind the nameless legions XVII, XVIII and XIX, which were annihilated by the Germanians at the battle of Teutoburg Forrest in 9 AD. This horrendous defeat in combination with the Great Illyrian Revolt of 6 AD to 9 AD nearly destroyed the empire. Germania was never invaded again, the numbers 17 to 19 were never again used to designate Roman legions and the names of these legions were wiped from the historical records.
And by adding, "for we are many" (in the Markan account) the demoniac seems to suggest two things:
First, his legion's numerical designation is not limited to one number but rather a lot of them, if not all of them. Before the Roman army became organized in separate legions, the entire army was referred to as "the legion".
Secondly, the demoniac is not saying the same thing twice when he says, "Legion, because we are many," but gives additional information. There are quite a few ways to indicate a large number in Greek, and the demoniac uses the very common word πολυς (polus), meaning many. But if he had specifically wanted to emphasize the hugeness of his demonic infection, he may have rather used words like μυριας (murias), meaning myriad or huge multitude, or πληθος (plethos), meaning crowd, or perhaps even αναριθμητος (anarithmetos), meaning innumerable. In stead he uses πολυς (polus), and perhaps not to indicate the huge quantity of demons inside him, but something a touch more sinister.
Roman legions were frequently named after the country they were stationed in or near (Legio I Germanica, Legio IV Macedonica, Legio IX Hispana, and so on). The word polus was also used to indicate the common people; the grey masses or hoi polloi (2 Corinthians 8:15). The man named Legion is basically saying that he's everybody; his demonic infection consists of the general populace of the Roman Empire. He is Israel and his demonic infection is the Roman occupation.
🔼The herd of swine
Pigs were unclean animals and wouldn't have existed in Palestine if it had been up to the Jews (Deuteronomy 14:8). Unfortunately, it wasn't. Palestine was occupied by Romans, and Romans wanted pigs to sacrifice in their temples; there was even a special pig-tax, although it's not wholly clear what that entailed. By sending the legion into the herd of swine, which subsequently destroys itself, Jesus appears to make a statement similar to "render to Caesar what belongs to Caesar" (Matthew 22:21). Since Jesus is Truth and Truth will always prevail, whatever systems of belief are enjoying their fleeting moment of support, they will essentially all evolve off the stage of human experience. Jesus seems to say that fighting them is folly; just let them go.
🔼Etymology of the name Legion
The name Legion is the same as the Greek noun λεγεων (legeon), meaning legion, which was imported from Latin and derives of a Latin verb that in turn came from Greek, namely λεγω (lego), meaning to speak intelligently:
The name Legion obviously means Legion, but the pun easily evades the modern reader. The demon possessed man was not simply a screaming, drooling fool but a man very much capable of intelligent discourse. He was naked and lived among the tombs but his name suggests order and quality.
In modern times the word demon came to denote a miniature devil, but in New Testament times this was not at all so. Greek mythology used the word δαιμων (daimon) for gods and goddesses and transitive for spirits and even fate and fortune in general. In Roman mythology, such a daimon was called a genius or numen. Liddell and Scot (A Greek-English Lexicon) connect the Greek noun daimon to the noun δαημων (daemon), meaning a knowing (skill in combat), but declare a more probable etymology from the verb δαιω (daio), meaning to divide or distribute destinies.
The Latin word genius denotes "the superior or divine nature which is innate in everything, the spiritual part, spirit," and from there "the tutelar deity or genius of a person, place, etc" and "the spirit of social enjoyment, fondness for good living, taste, appetite, inclination" (quoting Lewis and Short, A Latin Dictionary).
Spiros Zodhiates (The Complete Wordstudy Dictionary) notes that although Jesus encountered many demon-related challenges and His power over demons was absolute, He never showed anger or raised His voice to them. Demons always recognized Him and always at once realized that they were out of business.
Mark also tells the story of Jesus driving an unclean spirit out of a man, after which the onlookers (among which the freshly drafted disciples) recognize Jesus' actions not due to some undefined power, but to a new teaching (Mark 1:27). The man named Legion, therefore is not simply someone with a lot of evil spirits, but representative of the whole of Greek and Roman society; the entire Greco-Roman way of living and assessing reality, with which Jesus as the Word of God (Λογος, Logos, also derived from the verb λεγω) effortlessly competed.