The modern port is still sometimes called the "Port of Hercules". The 1907 Catholic Encyclopedia wrote, "From ancient times until the nineteenth century the port of Monaco was among the most important of the French Mediterranean coast, but now it has lost all commercial significance."
The Roman poet Virgil called it "that castled cliff, Monoecus by the sea" (Aeneid, VI.830). The commentator Servius's use of the passage (in R. Maltby, Lexicon of Ancient Latin Etymologies, Leeds) asserts, under the entry portus, that the epithet was derived:
The port is mentioned in Pliny the Elder's Natural History (III.v) and in Tacitus' Histories (III.42), when Valens was forced to put into the port (Fabius Valens e sinu Pisano segnitia maris aut adversante vento portum Herculis Monoeci depellitur).
In 1191, Holy Roman Emperor Henry VI granted suzerainty over the area to the city of Genoa, the native home of the Ligurians. On June 10, 1215, a detachment of Genoese Ghibellines led by Fulco del Cassello began the construction of a fortress atop the Rock of Monaco. This date is often cited as the beginning of Monaco's modern history.
As the Ghibellines intended their fortress to be a strategic military stronghold and center of control for the area, they set about creating a settlement around the base of the Rock to support the garrison; in an attempt to lure residents from Genoa and the surrounding cities, they offered land grants and tax exemption to new settlers.
François Grimaldi seized the Rock of Monaco in 1297; the area remained under the control of the Grimaldi family to the present day, except when under French control from 1793 to May 17, 1814. Designated as a protectorate of the Kingdom of Sardinia in 1815 by the Congress of Vienna after Napoleon's defeat, Monaco's sovereignty was confirmed by the Franco-Monegasque Treaty of 1861. The Prince of Monaco was an absolute ruler until a constitution was promulgated in 1911.
The famous Casino of Monte Carlo opened in 1863, organized by the Societé des Bains de Mer ("Sea-bathing Society"), which also ran the Hotel de Paris; taxes paid by the S.B.M. have been plowed into Monaco's infrastructure. Economic development was spurred in the late 19th century with a railway link to France. In July 1918, a treaty was signed providing for limited French protection over Monaco. The treaty, written into the Treaty of Versailles, established that Monegasque policy would be aligned with French political, military, and economic interests. One of the motivations for the treaty was the upcoming Monaco Succession Crisis of 1918.
While Prince Louis II's sympathies were strongly pro-French, he tried to keep Monaco neutral during World War II but supported the Vichy French government of his old army colleague, Marshall Philippe Pétain. Nonetheless, his tiny principality was tormented by domestic conflict partly as a result of Louis' indecisiveness, and also because the majority of the population was of Italian descent; many of them supported the fascist regime of Italy's Benito Mussolini. In 1943, the Italian Army invaded and occupied Monaco, setting up a fascist puppet government. Soon after, following Mussolini's fall in Italy, the German Army occupied Monaco and began the deportation of the Jewish population. Among them was René Blum, founder of the Opera, who died in a Nazi concentration camp. Under Prince Louis' secret orders, the Monaco police, often at great risk to themselves, warned people in advance that the Gestapo was planning on arresting them. The country was liberated as German troops retreated.
The current ruler, Prince Albert II, succeeded his father Prince Rainier III in 2005. Prince Rainier, in turn, had acceded to the throne following the death of his grandfather, Prince Louis II, in 1949.
The revised Constitution of Monaco, proclaimed in 1962, abolished capital punishment, provided for female suffrage, established a Supreme Court to guarantee fundamental liberties and made it difficult for a French national to transfer his or her residence there.
In 1993, Monaco became an official member of the United Nations with full voting rights. In 2002, a new treaty between France and Monaco clarifies that if there are no heirs to carry on the dynasty, the Principality will remain an independent nation, rather than be annexed by France. Monaco's military defense, however, is still the responsibility of France.
The principality's mild climate, attractive scenery, and gambling facilities have made Monaco world famous as a tourism and recreation centre.