Asconius Pedianus

A historian is a person who studies and writes about the past and is regarded as an authority on it. Historians are concerned with the continuous, methodical narrative and research of past events as relating to the human race; as well as the study of all history in time. Some historians are recognized by publications or training and experience. "Historian" became a professional occupation in the late nineteenth century as research universities were emerging in Germany and elsewhere.

Tiberius Claudius Caesar Augustus Germanicus was the fourth Roman emperor, ruling from AD 41 to 54. A member of the Julio-Claudian dynasty, Claudius was born to Drusus and Antonia Minor at Lugdunum in Roman Gaul, where his father was stationed as a military legate. He was the first Roman emperor to be born outside Italy. Nonetheless, Claudius was an Italian of Sabine origins.

Nero Claudius Caesar Augustus Germanicus, was the fifth Roman emperor and final emperor of the Julio-Claudian dynasty, reigning from AD 54 until his death in AD 68. He was adopted by the Roman emperor Claudius at the age of 13 and succeeded him on the throne. Nero was popular with the members of his Praetorian Guard and lower-class commoners in Rome and its provinces, but he was deeply resented by the Roman aristocracy. Most contemporary sources describe him as tyrannical, self-indulgent, and debauched. After being declared a public enemy by the Roman Senate, he committed suicide at age 30.

Marcus Tullius Cicero was a Roman statesman, lawyer, scholar, philosopher, and academic skeptic, who tried to uphold optimate principles during the political crises that led to the establishment of the Roman Empire. His extensive writings include treatises on rhetoric, philosophy and politics. He is considered one of Rome's greatest orators and prose stylists. He came from a wealthy municipal family of the Roman equestrian order, and served as consul in 63 BC.

Titus Livius, known in English as Livy, was a Roman historian. He wrote a monumental history of Rome and the Roman people, titled Ab Urbe Condita, ''From the Founding of the City'', covering the period from the earliest legends of Rome before the traditional founding in 753 BC through the reign of Augustus in Livy's own lifetime. He was on familiar terms with members of the Julio-Claudian dynasty and a friend of Augustus, whose young grandnephew, the future emperor Claudius, he exhorted to take up the writing of history.

Gaius Plinius Secundus, called Pliny the Elder, was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic Naturalis Historia, which became an editorial model for encyclopedias. He spent most of his spare time studying, writing, and investigating natural and geographic phenomena in the field.

The Natural History is a work by Pliny the Elder. The largest single work to have survived from the Roman Empire to the modern day, the Natural History compiles information gleaned from other ancient authors. Despite the work's title, its subject area is not limited to what is today understood by natural history; Pliny himself defines his scope as "the natural world, or life". It is encyclopedic in scope, but its structure is not like that of a modern encyclopedia. It is the only work by Pliny to have survived, and the last that he published. He published the first 10 books in AD 77, but had not made a final revision of the remainder at the time of his death during the AD 79 eruption of Vesuvius. The rest was published posthumously by Pliny's nephew, Pliny the Younger.

Madrid is the capital and most populous city of Spain. The city has almost 3.4 million inhabitants and a metropolitan area population of approximately 6.7 million. It is the second-largest city in the European Union (EU), and its monocentric metropolitan area is the second-largest in the EU. The municipality covers 604.3 km2 (233.3 sq mi) geographical area.