In modern historiography, the Western Roman Empire was the western provinces of the Roman Empire, collectively, during any period in which they were administered separately from the eastern provinces by a separate, independent imperial court. Particularly during the period from AD 395 to 476, there were separate, coequal courts dividing the governance of the empire into the Western provinces and the Eastern provinces with a distinct imperial succession in the separate courts. The terms Western Roman Empire and Eastern Roman Empire were coined in modern times to describe political entities that were de facto independent; contemporary Romans did not consider the Empire to have been split into two empires but viewed it as a single polity governed by two imperial courts for administrative expediency. The Western Empire collapsed in 476, and the Western imperial court in Ravenna disappeared by AD 554, at the end of Justinian's Gothic War. Though there were periods with more than one emperor ruling jointly before, the view that it was impossible for a single emperor to govern the entire Empire was institutionalized by emperor Diocletian following the disastrous civil wars and disintegrations of the Crisis of the Third Century. He introduced the system of the Tetrarchy in 286, with two senior emperors titled Augustus, one in the East and one in the West, each with an appointed subordinate and heir titled Caesar. Though the tetrarchic system would collapse in a matter of years, the East–West administrative division would endure in one form or another over the coming centuries. As such, the unofficial Western Roman Empire would exist intermittently in several periods between the 3rd and 5th centuries. Some emperors, such as Constantine I and Theodosius I, governed, if briefly, as the sole Augustus across the Roman Empire. On the death of Theodosius in 395, the empire was divided between his two infant sons, with Honorius as his successor in the West governing briefly from Mediolanum then from Ravenna, and Arcadius as his successor in the East governing from Constantinople. In 476, after the Battle of Ravenna, the Roman army in the West suffered defeat at the hands of Odoacer and his Germanic foederati. Odoacer forced the abdication of the emperor Romulus Augustulus and became the first King of Italy. In 480, following the assassination of the previous Western emperor Julius Nepos, the Eastern emperor Zeno dissolved the Western court and proclaimed himself the sole emperor of the Roman Empire. The date of 476 was popularised by the 18th-century British historian Edward Gibbon as a demarcating event for the fall of the Western Roman Empire and is sometimes used to mark the transition from Antiquity to the Middle Ages. Odoacer's Italy and other barbarian kingdoms, many of them representing former Western Roman allies that had been granted lands in return for military assistance, would maintain a pretense of Roman continuity through the continued use of the old Roman administrative systems and nominal subservience to the Eastern Roman court. In the 6th century, Emperor Justinian I re-imposed direct Imperial rule on large parts of the former Western Roman Empire, including the prosperous regions of North Africa, the ancient Roman heartland of Italy and parts of Hispania. Political instability in the Eastern heartlands, combined with foreign invasions, plague, and religious differences, made efforts to retain control of these territories difficult and they were gradually lost for good. Though the Eastern Empire retained territories in the south of Italy until the eleventh century, the influence that the Empire had over Western Europe had diminished significantly. The papal coronation of the Frankish king Charlemagne as Roman Emperor in 800 marked a new imperial line that would evolve into the Holy Roman Empire, which presented a revival of the Imperial title in Western Europe but was in no meaningful sense an extension of Roman traditions or institutions. The Great Schism of 1054 between the churches of Rome and Constantinople further diminished any authority the emperor in Constantinople could hope to exert in the West.

In a monarchy, a regent (from Latin regens 'ruling, governing') is a person appointed to govern a state pro tempore (Latin for 'for the time being') because the actual monarch is a minor, absent, incapacitated or unable to discharge their powers and duties, or the throne is vacant and a new monarch has not yet been determined. The rule of a regent or regents is called a regency. A regent or regency council may be formed ad hoc or in accordance with a constitutional rule. Regent is sometimes a formal title granted to a monarch's most trusted advisor or personal assistant. If the regent is holding the position due to their being in the line of succession, the compound term prince regent is often used; if the regent of a minor is their mother, and she is wife or widow of the king, she would be referred to as queen regent. If the formally appointed regent is unavailable or cannot serve on a temporary basis, a regent ad interim may be appointed to fill the gap. In a monarchy, a regent usually governs due to one of these reasons, but may also be elected to rule during the period when the royal line has died out. This was the case in the Kingdom of Finland and the Kingdom of Hungary, where the royal line was considered extinct in the aftermath of World War I. In Iceland, the regent represented the King of Denmark as sovereign of Iceland until the country became a republic in 1944. In the Polish–Lithuanian Commonwealth (1569–1795), kings were elective, which often led to a fairly long interregnum. During this period, the Roman Catholic primate (the Archbishop of Gniezno) served as the regent, and was called interrex (Latin: ruler 'between kings' as in Ancient Rome). In the small republic of San Marino, the two Captains Regent (Capitani Reggenti) are both elected for a six-month term as joint heads of state. Famous regency periods include that of the Prince Regent, later George IV of the United Kingdom, giving rise to many terms such as Regency era and Regency architecture. Strictly, this period lasted from 1811 to 1820, when his father George III was insane, though when used as a period label it generally covers a wider period. Philippe II, Duke of Orléans was Regent of France from the death of Louis XIV in 1715 until Louis XV came of age in 1723; this is also used as a period label for many aspects of French history, as Régence in French, again tending to cover a rather wider period than the actual regency. In the 16th century, Queen Catherine de Medici's acts as regent caused her to become arguably the most important woman in Europe, giving her name to an age. The equivalent Greek term is epitropos (επίτροπος), meaning overseer. As of 2025, Liechtenstein (under Alois, Hereditary Prince of Liechtenstein) and Luxembourg (under Guillaume, Hereditary Grand Duke of Luxembourg) are the only countries with active regencies. In 2016, Prem Tinsulanonda became the oldest regent of any nation, at the age of 96. He became the regent for Rama X of Thailand, who chose not to formally accede to the throne until the end of the mourning period for his father. Previously, this record was held by Prince Regent Luitpold of Bavaria, who was 91 at the end of his regency.

Politics (from Ancient Greek πολιτικά (politiká) 'affairs of the cities') is the set of activities that are associated with making decisions in groups, or other forms of power relations among individuals, such as the distribution of status or resources. The branch of social science that studies politics and government is referred to as political science. Politics may be used positively in the context of a "political solution" which is compromising and non-violent, or descriptively as "the art or science of government", but the word often also carries a negative connotation. The concept has been defined in various ways, and different approaches have fundamentally differing views on whether it should be used extensively or in a limited way, empirically or normatively, and on whether conflict or co-operation is more essential to it. A variety of methods are deployed in politics, which include promoting one's own political views among people, negotiation with other political subjects, making laws, and exercising internal and external force, including warfare against adversaries. Politics is exercised on a wide range of social levels, from clans and tribes of traditional societies, through modern local governments, companies and institutions up to sovereign states, to the international level. In modern states, people often form political parties to represent their ideas. Members of a party often agree to take the same position on many issues and agree to support the same changes to law and the same leaders. An election is usually a competition between different parties. A political system is a framework which defines acceptable political methods within a society. The history of political thought can be traced back to early antiquity, with seminal works such as Plato's Republic, Aristotle's Politics, Confucius's political manuscripts and Chanakya's Arthashastra.

Rome (Italian and Latin: Roma, pronounced [ˈroːma] ) is the capital city and most populated comune (municipality) of Italy. It is also the administrative centre of the Lazio region and of the Metropolitan City of Rome. A special comune named Roma Capitale with 2,746,984 residents in 1,285 km2 (496.1 sq mi), Rome is the third most populous city in the European Union by population within city limits. The Metropolitan City of Rome Capital, with a population of 4,223,885 residents, is the most populous metropolitan city in Italy. Its metropolitan area is the third-most populous within Italy. Rome is located in the central-western portion of the Italian Peninsula, within Lazio (Latium), along the shores of the Tiber Valley. Vatican City (the smallest country in the world and headquarters of the worldwide Catholic Church under the governance of the Holy See) is an independent country inside the city boundaries of Rome, the only existing example of a country within a city. Rome is often referred to as the City of Seven Hills due to its geography, and also as the "Eternal City". Rome is generally considered to be one of the cradles of Western civilization and Western Christian culture, and the centre of the Catholic Church. Rome's history spans 28 centuries. While Roman mythology dates the founding of Rome at around 753 BC, the site has been inhabited for much longer, making it a major human settlement for over three millennia and one of the oldest continuously occupied cities in Europe. The city's early population originated from a mix of Latins, Etruscans, and Sabines. Eventually, the city successively became the capital of the Roman Kingdom, the Roman Republic and the Roman Empire, and is regarded by many as the first-ever Imperial city and metropolis. It was first called The Eternal City (Latin: Urbs Aeterna; Italian: La Città Eterna) by the Roman poet Tibullus in the 1st century BC, and the expression was also taken up by Ovid, Virgil, and Livy. Rome is also called Caput Mundi (Capital of the World). After the fall of the Empire in the west, which marked the beginning of the Middle Ages, Rome slowly fell under the political control of the Papacy, and in the 8th century, it became the capital of the Papal States, which lasted until 1870. Beginning with the Renaissance, almost all popes since Nicholas V (1447–1455) pursued a coherent architectural and urban programme over four hundred years, aimed at making the city the artistic and cultural centre of the world. In this way, Rome first became one of the major centres of the Renaissance and then became the birthplace of both the Baroque style and Neoclassicism. Famous artists, painters, sculptors, and architects made Rome the centre of their activity, creating masterpieces throughout the city. In 1871, Rome became the capital of the Kingdom of Italy, which, in 1946, became the Italian Republic. In 2019, Rome was the 14th most visited city in the world, with 8.6 million tourists, the third most visited city in the European Union, and the most popular tourist destination in Italy. Its historic centre is listed by UNESCO as a World Heritage Site. The host city for the 1960 Summer Olympics, Rome is also the seat of several specialised agencies of the United Nations, such as the Food and Agriculture Organization, World Food Programme, International Fund for Agricultural Development and UN System Network on Rural Development and Food Security. The city also hosts the European Union (EU) Delegation to the United Nations (UN), Secretariat of the Parliamentary Assembly of the Union for the Mediterranean, headquarters of the World Farmers' Organisation, multi-country office of the United Nations High Commissioner for Refugees, Human Resources Office for International Cooperation of the United Nations Department of Economic and Social Affairs, headquarters of the International Labour Organization Office for Italy, headquarters of the WORLD BANK GROUP for Italy, Office for Technology Promotion and Investment in Italy under the United Nations Industrial Development Organization, Rome office of the United Nations Interregional Crime and Justice Research Institute, and support office of the United Nations Humanitarian Response Depot, as well as the headquarters of several Italian multinational companies such as Eni, Enel, TIM, Leonardo, and banks such as BNL. Numerous companies are based within Rome's EUR business district, such as the luxury fashion house Fendi located in the Palazzo della Civiltà Italiana. The presence of renowned international brands in the city has made Rome an important centre of fashion and design, and the Cinecittà Studios have been the set of many Academy Award–winning movies.