Rubicon

The Rubicon (Latin: Rubico; Italian: Rubicone [rubiˈkoːne]; Romagnol: Rubicôn [rubiˈkoːŋ]) is a shallow river in northeastern Italy, just south of Cesena and north of Rimini. It was known as Fiumicino until 1933, when it was identified with the ancient river Rubicon, crossed by Julius Caesar in 49 BC. The river flows for around 80 km (50 mi) from the Apennine Mountains to the Adriatic Sea through the south of the Emilia-Romagna region, between the towns of Rimini and Cesena.

The Latin word Rubico comes from the adjective rubeus, meaning "red". The river was so named because its waters are colored red by iron deposits in the riverbed.

During the Roman Republic, the Rubicon marked the boundary between the Roman province of Cisalpine Gaul and the areas directly controlled by Rome and its socii (allies), to the south. On the north-western side, the border was marked by the river Arno, a much wider and more important waterway, which flows westward from the Apennine Mountains (the Arno and the Rubicon rise not far from each other) into the Tyrrhenian Sea.

In 49 BC, perhaps on 10 January, Julius Caesar led a single legion, Legio XIII Gemina, south over the Rubicon from Cisalpine Gaul to Italy to make his way to Rome. In doing so, he deliberately broke the law limiting his imperium, making armed conflict inevitable. Suetonius ("Divus Julius" 32) depicts Caesar as undecided as he approached the river, and attributes the crossing to a supernatural apparition (thus also in Lucan, 1.185-203). It was reported that Caesar dined with Sallust, Hirtius, Gaius Oppius, Lucius Cornelius Balbus, and Servius Sulpicius Rufus on the night after his crossing.

According to Suetonius, Caesar uttered the famous phrase alea iacta est ('the die is cast') upon crossing the Rubicon, signifying that his action was irreversible. The phrase "crossing the Rubicon" is now used to refer to committing irrevocably to a grave course of action, similar to the modern phrase "passing the point of no return," but with the added connotation of risking danger. The presence of Caesar and his legion in Italy forced Pompey, the consuls, and a large part of the senate to flee Rome. Caesar's victory in the subsequent civil war ensured that he would never be punished for his actions.

After Caesar's crossing, the Rubicon was a geographical feature of note until about 42 BC, when Octavian merged the Province of Cisalpine Gaul into Italia and the river ceased to be the extreme northern border of Italy. The decision robbed the Rubicon of its importance, and the name gradually disappeared from the local toponymy.

After the fall of the Western Roman Empire, and during the first centuries of the Middle Ages, the coastal plain between Ravenna and Rimini was flooded many times. The Rubicon, like other small rivers of the region, often changed its course during this period. For this reason, and to supply fields with water after the revival of agriculture in the late Middle Ages, during the 14th and 15th centuries, hydraulic works were built to prevent other floods and to regulate streams. As a result of this work, these rivers started to flow in straight courses, as they do today.

With the revival during the fifteenth century of interest in the topography of ancient Roman Italy, the matter of identifying the Rubicon in the contemporary landscape became a topic of debate among Renaissance humanists. To support the claim of the river Pisciatello, a spurious inscription forbidding the passage of an army in the name of the Roman people and Senate, the so-called Sanctio, was placed by a bridge on that river. The Quattrocento humanist Flavio Biondo was deceived by it; the actual inscription is conserved in the Museo Archeologico, Cesena. As the centuries went by, several rivers of the Adriatic coast between Ravenna and Rimini have at times been said to correspond to the ancient Rubicon.