The legend of Carthaginian general Hannibal—famed for leading some 30,000 soldiers and 37 elephants across the Alps into Italy during the Second Punic War—had to start somewhere. And now, researchers think they may know where.

As Manuel P. Villatoro reports for Spanish newspaper ABC, an interdisciplinary team says it has found the long-sought-after site of Hannibal’s first major victory: the 220 B.C. Battle of the Tagus.

Due to mismatched accounts by classical historians Polybius and Livy, as well as scant archaeological evidence, historians have debated the battle’s exact location for more than 200 years. Previously proposed sites include Toledo, Talavera de la Reina, Aranjuez, Colmenar de Oreja and Fuentidueña, reports Vicente G. Olaya for Spanish newspaper El País.

The new study arrived at its suggested location by combining battle accounts from antiquity with modern analysis of the shape and flow of the Tagus River and its surrounding landscape. Per the paper, the researchers suggest the site of the Battle of the Tagus is between the cities of Driebes and Illana in Spain’s Guadalajara province.

Hannibal mounted his infamous invasion of Italy during the Second Punic War against Rome, which spanned 218 B.C. to 201 B.C. But two years before he took on Rome, the Carthaginian general fought a pivotal battle closer to home.

Polybius and Livy tell of the 27-year-old Hannibal’s army being ambushed as it returned to its base in Qart Hadasht, located in modern-day Cartagena, after defeating the Vettones tribe and conquering Helmática, near the modern city of Salamanca in northwest Spain. As Isambard Wilkinson notes for the Times, the general’s 25,000 soldiers and 40 war elephants are said to have faced a force of 100,000 Iberians from the Carpetani, Vettone and Olcade tribes near the Tagus River.

The tactical details of the battle foreshadowed the young general’s prowess as a commander. With his troops outnumbered four to one, Hannibal moved to avoid fighting out in the open, preventing what would have likely been a bloodbath.

When the Carthaginian army fled to the opposite side of the Tagus, the Iberians followed in hot pursuit, no doubt thinking they had the smaller army on the run. In actuality, Hannibal had led them into a trap that neutralized their superior numbers.

The Carthaginians funneled the Iberian tribes into narrow crossings where the river’s swift waters were shallow enough to ford on foot. To prevent any alternative crossings, Hannibal’s army also fortified the riverbank. The Iberians were forced to cross via the natural fords, where they were easy targets for Hannibal’s cavalry. Others lost their footing and drowned in the river; those who managed to cross successfully were met by the Carthaginian infantry and its squadron of war elephants.

Despite the element of surprise, the Iberian tribes proved to be no match for Hannibal’s tactical genius. The authors of the new research arrived at the stunning victory’s proposed location by taking historical, geographical and geological factors into account, per the Times.

First, the researchers determined the fastest overland route Hannibal’s forces could have used to reach their destination in modern-day Cartagena. The route the team identified crossed the Tagus near Driebes, which, incidentally, would place the battle close to a known settlement of the Carpentani tribe.

“The decision to attack Hannibal there was made by the Carpetanis, who knew the environment well and which also gave them leadership within the coalition with Vettones and Olcades,” Emilio Gamo Pazos, lead author of the study and an archaeologist at Spain’s National Museum of Roman Art, tells El País.

Next came the question of the river. Geologists on the team suggest that, given the local geology, it’s plausible the same fords used in the battle are present today, according to El País. This framing allowed the team to zero in on the remnants of a rectangular structure they hypothesize could have been part of Hannibal’s fortifications.

Dovetailing with this potential vestige of the fortifications is the nearby hill of El Jardin, which would have afforded the general an elevated position from which to orchestrate the battle.

To cement their initial findings, the researchers tell El País that they intend to conduct follow-up archaeological studies aimed at identifying more definitive signs of the Carthaginian army—including elephant bones.