Extent of the Roman Empire in Italy at the height of Roman power spanning all of the Italian peninsula and much of western Europe and the Mediterranean.

Early barbarian invasions bring Ostrogoths and Visigoths onto the Italian peninsula in the fourth and fifth centuries eventually leading to the fall of the Roman Empire.

German invader Odoacer otherthrew the last western Roman Emperor, Romulus Augustulus in 476 BC, ruling peacefully thereafter from Ravenna until 493.

Theodoric of the Ostrogoths killed Odoacer in 493 to become the new king of Italy and establish the Ostrogothic Kingdom.

In the 6th century, Byzantine Emperor Justinian successfully re-conquered much of the former Western Roman Empire. However his reconquests were short-lived, coming to an end after the arrival of the Lombards in 568 after which Byzantine terrritories were confined to the northeast and southernmost tip of the Italian peninsula.

The Lombards, a Germanic people, first entered Italy as paid mercenaries for the Byzantine army under general Narses. They soon overtook the Byzantines, first conquering Pavia in 572 and eventually possessing almost the entire peninsula.

Charlemagne conquered the Lombard Kingdom of Italy in 774. By 800, he possessed most of western Europe and was crowned Emperor by Pope Leo III, ruling until his death in 814.

Charlemagne's son Louis the Pious inherited his father's empire in 814. After his death in 840, his lands were partitioned between his three eldest sons: Lothar, Louis the German, and Pippin I. In the Treaty of Verdun of 843, Lothar recieves the middle kingdom of Italy, becoming Emperor Lothair I. When Lothar died in 855, his kingdom was further divided between his remaining brothers, Charles the Bald and Louis the German.

As the divided Frankish Empire struggled to mainitain control over its sprawling territories, Viking and Magyar invaders threatened the weakened European west in the 9th and early 10th centuries.

The Germanic Ottonians emerge as a new European super power in the 10th century, invading Italy under Otto I in 951 and taking over those Italian possessions previously under Carolingian power. Otto I is crowned King of Italy in 961, thus beginning a period of German imperial interests in Italy that would last into the 13th century.

The Salians were part of a Frankish dynasty that took over the Ottonian possessions in Italy. Its four kings ruled from 1024 to 1125, each receiving the title "Holy Roman Emperor" during their reign.

Norman conquerers of French and Germanic origin established a kingdom in Sicily and southern Italy in the early 11th century, eliminating the Lombard principalities and independent duchies. By 1072, the Normans had removed the foreign powers of the Byzantines in southern Italy and the Arabs in Sicily.

After 1130, Roger II is crowned King of Sicily, Calabria, and Apulia, uniting all Italian Norman conquests under the newly formed Kingdom of Sicily.

Frederick I Barbarossa is crowned King of Italy in Pavia in 1154 and Holy Roman Emperor by Pope Adrian IV in 1155, effectively taking all of northern Italy under German control as the Kingdom of Italy.

Frederick II of Houhenstaufen inherited the Kingdom of Sicily from his mother, Constance of Sicily in 1194. As Holy Roman Emperor until 1250, Frederick possessed almost the entire Italian peninsula excluding the Papal States during his reign. The Houhenstaufen Dynasty continued to rule in Italy until 1266 when the execution of Manfred by the troops of Charles of Anjou at the Battle of Benevento brought an end to the family's Italian line.

The territories that made up the Patrimony of Saint Peter marked the areas privately owned by the Church which began to grow significantly during the 6th and 7th centuries. Increasing threats from Lombard invaders encouraged the people of Rome to give their allegiance to the bishop as opposed to the emperor, thus elevating the Church's status. Rome's self-sufficiency granted by the disinterest of Byzantine and Lombard rulers allowed for the development of the bishopric into the Papacy as the duties of the bishop exceeded the qualifications of a mere spiritual leader.

In the 11th century the Church separated from secular rule, firmly establishing a papal court at the Curia in Rome and developing its own laws (canon law). In 1509, a council of reformers declared that a College of Cardinals rather than a secular ruler would select the pontiff in all future papal elections. Futhermore, the Dictus Papae of 1075 finally defined the extent of the Pope's authority as head of the Catholic Church.

The increasing power of the Church during the 12th century threatens Imperial authority in northern Italy and sparked an ongoing struggle between the Papacy and the Germanic emperors. Rival political factions arose in favor of the respective parties, the Guelphs siding with the Church and the Ghibellines with the Emperor.

Both Frederick I Barbarossa and his son Frederick II campaigned persistently against Rome, placing the Papal Sates in a state of constant battle with the Holy Roman Emperor until the death of Frederick II in 1250.

The French city of Avignon maintained the seat of the Roman Church from 1305 to 1377, ruled by four French popes in succession. When the seat of the Church returned to the Vatican in Rome in 1378, the College of Cardinals carefully insured that an Italian, Neapolitan Pope Urban VI, would take the place of the last French pontiff. Angered by the College's actions, the French elected their own pope to rule from the court in Avignon, refusing to acknowledge the Roman pope in favor of their own Pope Clement VII. This disagreement divided loyalties across Europe, generating a rift that would last for nearly forty years.

The conflict was resolved in 1418 by the Council of Constance which reestablished Rome as the true seat of the papacy with the election of Pope Martin V. Though many French loyalists continued to vie for the seat to remain in Avignon, their efforts to install a French pope were futile and the Church remained in Rome thenceforth.

From 1198 to 1216, Pope Innocent II helped to stabilize political power in Italy by administering the Papal States, which by the 13th century had expanded from the area surrounding Rome to cover most of central Italy. The territories owned and governed by the Papal States spanned the entire width of the peninsula bordered by Tuscany and Lombardy in the north and the Kingdom of Naples in the south.

By 1080, Lucca and Pisa rejected bishopric and imperial overlordship in favor of establishing their own communes, protected by regional nobility. The communes spread beyond Lombardy and Tuscany during the late 11th and 12th centuries, gradually evolving into city-states with their own internal governments.

The success of Italian traders in the 12th century transformed northern Italy into a flourishing European trade center with maritime routes that extended from ports like Venice and Genoa to cover the entire Mediterranean and Atlantic coasts of Europe. Increased wealth associated with the burgeoning trade market supported the growth of the northern city-states as they became European centers of learning and culture during the Renaissance.

Titled the Lombard League, twelve united northern Italian cities including Milan, Genoa, and Pavia defeated the German king Frederick I Barbarossa in 1167 at Legnano, forcing a truce and establishing their independence. In the Peace of Constance of 1183, the League agreed to Imperial taxation and protection in return for peace between northern Italy and the Holy Roman Empire.

Though initally the city-states relied on the governance of collaborating local elites, as the dominant states extended their territories beyond the capital cities in the 15th century, they slowly began to develop a more centralized government based on a single ruling family. While Genoa and Venice both maintained their republican regimes, most of the other city-states were ruled by a noble signoria, the so-called Renaissance prince of Machiavellian fame.

For the most part the city-states of northern Italy reached their peaks during the Renaissance, after which the once prosperous industrial areas faced a period of decline early in the 17th century with the extensive loss of export markets to northern European competitors. Eventually the more powerful city-states like Florence, Milan, and Venice took the lesser cities and their surrounding areas under their influence to become governed as regional states, thus ending the age of the city-states.

In 1454, the Treaty of Lodi established peace between the feuding northern states by defining the permanent boundaries of the Milanese and Venetian territories. The treaty secured a balance of power in northern Italy that excluded the smaller states and confirmed the dominance of Milan, Venice, and its ally Florence.

As the dominant noble family of Milan, the Visconti ruled over the state from 1277 to 1447. In 1387, with aims to submit all of Italy to Visconti rule, Giangaleazzo Visconti threatened Venice and occupied Verona, Vicenza, Belleno, and Feltre. After taking over Bologna, Pisa, and Sienna, Giangaleazzo had control of the entire region of Lombardy, acquiring the title of duke in 1395. Before he could take Florence as well, the duke's ambitions were halted by his death in 1402.

The Medici family gathered prominence as a successful banking family under Cosimo de'Medici in the 13th century Republic of Florence. Officially the Medici were merely citizens of the Republic, but their influence was such that by the 15th century the signoria of the Republic was ruled predominately by Medici factions. Florence was relieved briefly of its Medici overlords in 1495 when Piero di Lorenzo de'Medici fled from Italy, however the Spanish reinstated the Medici in 1512 and effectively put an end to the Republic of Florence.

In response to the Milanese campaigns started by Giangaleazzo to expand Milanese territory, in 1406 Florence took over Tuscany and occupied Pisa.

Under the Venetian Republic, which lasted well into the 18th century, Venice expanded to possess all of northeastern Italy and many settlements outside of the peninsula including Istria and Dalmatia. The Republic's success was in a large part made possible by the wealth generated from its control of European trade in the Levant.

The Republic of Genoa was established in the 11th century as a self-governing commune, eventually expanding to include most of Liguria including the island of Corsica. In 1797, the Republic of Genoa became the Republic of Liguria until 1805 when it was annexed by the French Empire.

The French House of Savoy occupied and governed northern Italian territories bordering Genoa up until the 18th century when their possessions became known as the Kingdom of Sardinia.

After 1266, the Kingdom of Sicily was ruled by Charles of Anjou until the Sicilian Vespers in 1282 when the displeased Sicilian Barons invited Peter of Aragon to take over the island of Sicily, restricting Angevin territories to the peninsula and renaming them the Kingdom of Naples.

Charles VII of France invaded and occupied Naples from 1494 to 1495, claiming the previously Aragonese territories as Angevin property. Thereafter, Italy became a battleground for the Spanish and French powers, sparking the beginning of the Italian Wars which characterized the early 16th century.

Fearing Charles VII's increasing power, the majority of Italian troops join with the Spanish army in support of Alfonso II of Naples, forming the anti-French League of Venice. Charles VII was defeated in 1495 and his garrisons recaptured by the Aragonese allies thus returning power to Spain.

Habsburg Charles V of Spain increased Spanish holdings in Italy as Holy Roman Emperor from 1530 to 1558. Already in possession of both Naples and Sicily, during his reign Charles V also conquered Milan and its territories thus leaving only Venice and the Papal States outside of Habsburg control.

The Spanish Habsburg family ruled in Italy from 1530 until 1701 when the War of Spanish Succession decided the next rulers of Italy.

The end of Habsburg power brings about the War of Spanish Succession, lasting from 1701 to 1714. The Treaties of Utrecht and Rastatt ended the threat of a union between Spain and France and bequeathed most of the Spanish territories in Italy to the Austrians with the agreement that should the rulers of either Spain or Austria decide to take the throne in their own country, they would cede their Italian territories.

In 1759 Bourbon Charles III of Spain renounced Naples and Sicily after assuming the throne of Madrid. Likewise, Peter Leopold renounced Tuscany in 1790, but Lombardy remained part of the Austrian Empire.

After the Revolution in France, French revolutionaries invaded Italy in 1796 with the intent of conquering the peninsula. They established the Italian Republic which lasted until 1799, after which it became the Cisalpine Republic and absorbed the territories south of the Po River including Modena, Reggio Emilia, and the Republic of Venice.

Napoleon was crowned emperor in 1804, after which he divided the Italian states among his family. In 1805 the former Italian Republic became the Kingdom of Italy, governed by Napoleon's stepson Eugene Beauharnais. In the same year Napoleon made his sister Paolina Borghese Duchess of Parma, Guastella, and Piacenza, and after the defeat of the Bourbon rulers, his brother Joseph received Naples. Once Napoleon had annexed Tuscany, the region was given to his other sister, Elisa Baciochi. His final gift went to his son, Napoleon II, who became King of Rome in 1811 after its annexation to France in 1809.

From 1814 to 1815 after the defeat of Napoleon at Waterloo, the Congress of Vienna met to discuss the redistribution of Napoleon's conquests. In an attempt to restore the pre-revolutionary independent regimes in Italy, many territories were returned to their previous rulers. Lombardy -Venetia was granted to Austria and the Habsburg princes regained control of the Grand Duchy of Tuscany and the Duchy of Modena. The Papal States remained under the control of the Pope and returned to their former extent while the King of Sardinia was restored in Piedmont, Nice, and Savoy, receiving also the addition of Genoa. Napoleon's wife Marie Louise was given the Duchies of Parma, Piacenza and Guastalla and finally, the Bourbon King Ferdinand the IV of Sicily returned to his throne in the Kingdom of Naples.

The activity of the French revolutionaries in Italy had ignited a rampant nationalism that could not be subdued by the restoration of the old governments so the period following the Congress of Vienna was characterized by revolution and unrest amidst the Italian states. After a series of unsuccessful revolts halted by the Austrian troops of the Holy Alliance, the Revolutions of 1848 to 1849 finally began the process of uniting the Italian states under a single nation despite their failure to remove the Austrians from Italy.

The War of Independence against Austria began in 1859 and in 1860, Italian military leader Giuseppe Garibaldi backed by his Thousand volunteers successfully captured southern Italy and took the title of dictator in the name of Victor Emmanuel II. After a series of battles, Italy finally completed the process of political unification and the first Italian parliament proclaimed Victor Emanuel II of Savoy king of Italy in 1861.

Though the end of the War of Independence against Austria marked the formation of Italy as a unified nation, it was not until later in the 19th and early 20th centuries that the shape of Italy appeared as it does today. The Kingdoms of Lombardy and Venetia were added after 1866, though the connecting area known as South Tyrol was not acquired until the 1920s. Even the papacy fought unification and it was not until the Italians occupied Rome in the 1870s that the pope gave up his temporal power over the Papal States but retained his spiritual authority as head of the Catholic Church.