Hannibal was born in 247 B.C.E. to a Carthaginian commander who gained fame in the First Punic War. Now, if you are like me and have no idea what most of what I just wrote means, here's a little background info. Carthage is basically a suburb of present-day Tunis (Tunisia), although it has been an urban center for around 3,000 years. The Carthaginian Empire grew from the Phoenician colony and flourished in the 3rd century B.C.E. - corresponding with the Hellenistic Era. Now, I know about Hellenistic Greece because they made some damn fine sculptures, but if you are unfamiliar with that era it is the time after Alexander the Great's unification of a vast territory including the eastern Mediterranean seaboard and parts of the middle east. His empire broke down quickly after his death in 323 B.C.E, however, and about a hundred and fifty years later, we find ourselves in the midst of the Punic Wars - probably the largest wars that had taken place up to that point - which were being fought between the Carthaginian Empire and the Roman Republic. Here's a break down of who had what territory:
The Roman senate wasn't too worried - they felt that the land was secure, and that there was no way Hannibal would be able to make it past the natural wall of the Alps. Hannibal was determined, and made his way with extraordinary troops - nearly 45,000 men with him and 37 war elephants. He fought his way through various outcroppings of Roman soldiers, crossed the Pyrenees mountains, and fought his way across southern France. The Romans sent some reinforcements, but weren't too worried. Hannibal was a cunning military leader and worked his way through by using a great deal of strategy, including a number of sneak attacks.
When Hannibal reached the Alps, however, his primary enemy was nature, not Roman soldiers. We have some accounts of Hannibal's journey that come from Roman historians such as Livy (unfortunately Carthaginian records are mostly non-existent). Here's what Livy had to say about how the Alps appeared to Hannibal and his troops:
The nature of the mountains was not, of course, unknown to his men by rumor and report - and rumor commonly exaggerates the truth; yet in this case all tales were eclipsed by the reality. The dreadful vision was now before their eyes: the towering peaks, the snow clad pinnacles soaring to the sky, the rude huts clinging to the rocks, beasts and cattle shriveled and parched with cold, the people with their wild and ragged hair, all nature, animate and inanimate, stiff with frost: all this, and other sights the horror of which words cannot express, gave a fresh edge to their apprehension. - livy
From what I have been able to glean, it sounds as if Hannibal's journey through the Alps took about two weeks and was fraught with difficulty. First off, it was cold. Yuck. Secondly, they were frequently at treacherous altitudes and on poorly hewn paths. Third, many of the alpine villagers fought on the side of the Roman Republic and attempted to thwart Hannibal's advancements. Fourth, even if Hannibal could speak with his troops and try to rally them, the animals proved a significant challenge. According to Livy, the horses that were brought were terrified by the noise of the troop movement in some narrow passages, which was "echoing and re-echoing from the hollow cliffs and woods, they [the horses] were soon out of control...lashing out in agony and fear, causing serious losses...many non-combatants, and not a few soldiers were flung over the sheer cliffs which bounded each side of the pass, and fell to their deaths thousands of feet below."
One of the most well known facts about Hannibal's trek is his use of elephants, which ended up being both a blessing and a curse. They took a great deal of time getting through the narrow and precipitous parts of the paths, however the native Alpine villagers had never seen any creature like them before and were reluctant to go near. In the end, all but a few of the enormous beasts perished in the brutal journey.
Altogether it took 9 days to reach the summit after taking wrong paths (partially due to deception on the part of guides from the villages). They were exhausted, and rested 2 days at the summit, but to add insult to their injuries, it started to snow. To rally the troops, Hannibal spoke out saying "my men, you are at this moment passing the protective barrier of Italy - nay more, you are walking over the very walls of Rome. Henceforward all will be easy going - no more hills to climb. After a fight or two you will have the capital of Italy, the citadel of Rome, in the hollow of your hands" (Livy).
As they journeyed on, they were thwarted by impasses, and the men at the front of the march would trample fresh snow on top of old snow, causing the old snow to turn to ice and leaving no foothold for the troops at the end, giving them no option but to, according to Livy's account, "roll and slither on the smooth ice and melting snow."
Eventually they even had to cut through rock, which brought about one of the most ingenious components of the trek: they would cut down trees, set them on fire on top of the rock layers, would wait for the rock to get hot, and then would fling their rations of sour wine on the rock, with the temperture juxtoposition causing cracks in the rock which they would then widen using their picks to carve a zig zag track.
When Hannibal finally arrived in Italy his number had shrunk considerably to around 24,000 men (about half what he had starting his alpine trek) and just a few elephants. By winning a few minor victories in a row, Hannibal was able to bring in warriors from other tribes and to gain a stronghold in Northern Italy. His journey continued to be a struggle (he even lost an eye during his crossing of the Apennines), and as he continued to move forward eventually lost more of his forces and the remaining elephants before arriving in Etruria (just north of Rome). He had a decisive win in the battle of Lake Trasimene - it was one of the most costly ambushes the Romans had sustained. Although inferior in numbers, Hannibal managed to use traps and cunning to continue beating Roman forces. In the battle of Cannae, Hannibal's men killed or captured an estimated 50-70,000 Romans. His troops killed several consuls, and eighty senators (25-30% of the governing body). It was a catastrophic defeat - one of the bloodiest battles of human history. Hoever, despite Hannibals successes, he eventually ended in a stalemate as he received no further rinforcements from Carthage and was unable to attack the city of Rome. After nearly 15 years of fighting in Italy, Hannibal was recalled to Carthage.
Although Hannibal was unable to defeat the Roman Republic, his tactical ingenuity is still heralded today, and his trek across the Alps continues to be an epic chapter in military history.