Roman emperor

Titus Aelius Hadrianus Antoninus Pius (/ˌæntəˈnaɪnəs ˈpaɪəs/; Latin: [antoːˈniːnus ˈpius]; 19 September 86 – 7 March 161) was Roman emperor from AD 138 to 161. He was the fourth of the Five Good Emperors from the Nerva–Antonine dynasty.

Born into a senatorial family, Antoninus held various offices during the reign of Emperor Hadrian. He married Hadrian's niece Faustina, and Hadrian adopted him as his son and successor shortly before his death. Antoninus acquired the cognomen Pius after his accession to the throne, either because he compelled the Senate to deify his adoptive father, or because he had saved senators sentenced to death by Hadrian in his later years. His reign is notable for the peaceful state of the Empire, with no major revolts or military incursions during this time. A successful military campaign in southern Scotland early in his reign resulted in the construction of the Antonine Wall.

Philip I (Latin: Marcus Julius Philippus; c. 204 – September 249), commonly known as Philip the Arab, was Roman emperor from 244 to 249. After the death of Gordian III in February 244, Philip, who had been Praetorian prefect, rose to power. He quickly negotiated peace with the Sasanian Empire and returned to Rome to be confirmed by the Senate. According to many historians, he was possibly the first Christian Roman Emperor.

Although his reign lasted only five years, it marked an unusually stable period in a century that is otherwise known for having been turbulent. Near the end of his rule, Philip commemorated Rome's first millennium. In September 249 he was killed during or shortly after the Battle of Verona against the usurper Trajan Decius, who was subsequently recognized by the Senate as his successor.

The Gothic War between the Byzantine Empire during the reign of Emperor Justinian I and the Ostrogothic Kingdom of Italy took place from 535 to 554 in the Italian peninsula, Dalmatia, Sardinia, Sicily, and Corsica. It was one of the last of the many Gothic wars against the Roman Empire. The war had its roots in the ambition of the Byzantine emperor Justinian I to recover the provinces of the former Western Roman Empire, which the Romans had lost to invading barbarian tribes in the previous century, during the Migration Period.

The war followed the Roman reconquest of the diocese of Africa from the Vandals. Historians commonly divide the war into two phases. The first phase lasts from 535 to the fall of the Ostrogothic capital Ravenna in 540, and the apparent reconquest of Italy by the Byzantines. The second phase from 540/541 to 553 featured a Gothic revival under Totila, which was suppressed only after a long struggle by the Roman general Narses, who also repelled an invasion in 554 by the Franks and Alamanni.

Diocletian (/ˌdaɪ.əˈkliːʃən/ DY-ə-KLEE-shən; Latin: Gaius Aurelius Valerius Diocletianus; Ancient Greek: Διοκλητιανός, romanized: Diokletianós; 242/245 – 311/312), nicknamed Jovius, was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia. As with other Illyrian soldiers of the period, Diocles rose through the ranks of the military early in his career, serving under Aurelian and Probus, and eventually becoming a cavalry commander for the army of Emperor Carus. After the deaths of Carus and his son Numerian on a campaign in Persia, Diocles was proclaimed emperor by the troops, taking the name "Diocletianus". The title was also claimed by Carus's surviving son, Carinus, but Diocletian defeated him in the Battle of the Margus.

Diocletian's reign stabilized the empire and ended the Crisis of the Third Century. He initiated the process of the Roman Empire split and appointed fellow officer Maximian as Augustus, co-emperor, in 286. Diocletian reigned in the Eastern Empire, and Maximian reigned in the Western Empire. Diocletian delegated further on 1 March 293, appointing Galerius and Constantius as junior colleagues (each with the title Caesar), under himself and Maximian respectively. Under the Tetrarchy, or "rule of four", each tetrarch would rule over a quarter-division of the empire. Diocletian secured the empire's borders and purged it of all threats to his power. He defeated the Sarmatians and Carpi during several campaigns between 285 and 299, the Alamanni in 288, and usurpers in Egypt between 297 and 298. Galerius, aided by Diocletian, campaigned successfully against Persia, the empire's traditional enemy, and in 299, he sacked their capital, Ctesiphon. Diocletian led the subsequent negotiations and achieved a lasting and favorable peace.

The Tetrarchy was the system instituted by Roman emperor Diocletian to govern the ancient Roman Empire by dividing it between two emperors, the augusti, and their junior colleagues and designated successors, the caesares. It was kept in place between AD 293 and 313.

Initially Diocletian chose Maximian as his caesar in 285, raising him to co-augustus the following year; Maximian was to govern the western provinces and Diocletian would administer the eastern ones. The role of the augustus was likened to Jupiter, while his caesar was akin to Jupiter's son Hercules. Galerius and Constantius were appointed caesares in March 293. Diocletian and Maximian retired on 1 May 305, raising Galerius and Constantius to the rank of augustus. Their places as caesares were in turn taken by Valerius Severus and Maximinus Daza.

Honorius (/hoʊˈnɔːriəs/; 9 September 384 – 15 August 423) was Roman emperor from 393 to 423. He was the younger son of emperor Theodosius I and his first wife Aelia Flaccilla. After the death of Theodosius in 395, Honorius, under the regency of Stilicho, ruled the western half of the empire while his brother Arcadius ruled the eastern half. His reign over the Western Roman Empire was notably precarious and chaotic. In 410, Rome was sacked for the first time since the Battle of the Allia almost 800 years prior.

Arcadius (Ancient Greek: Ἀρκάδιος Arkadios; c. 377 – 1 May 408) was Roman emperor from 383 to his death in 408. He was the eldest son of the Augustus Theodosius I (r. 379–395) and his first wife Aelia Flaccilla, and the brother of Honorius (r. 393–423). Arcadius ruled the eastern half of the empire from 395, when their father died, while Honorius ruled the west. In his time, he was seen as a weak ruler dominated by a series of powerful ministers and by his wife, Aelia Eudoxia.

Public works are a broad category of infrastructure projects, financed and procured by a government body for recreational, employment, and health and safety uses in the greater community. They include public buildings (municipal buildings, schools, and hospitals), transport infrastructure (roads, railroads, bridges, pipelines, canals, ports, and airports), public spaces (public squares, parks, and beaches), public services (water supply and treatment, sewage treatment, electrical grid, and dams), environmental protection (drinking water protection, soil erosion reduction,wildlife habitat preservation, preservation and restoration of forests and wetlands) and other, usually long-term, physical assets and facilities. Though often interchangeable with public infrastructure and public capital, public works does not necessarily carry an economic component, thereby being a broader term. Construction may be undertaken either by directly employed labour or by a private operator.

Public works has been encouraged since antiquity. The Roman emperor Nero encouraged the construction of various infrastructure projects during widespread deflation.

Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian (Latin: Octavianus), was the founder of the Roman Empire, who reigned as the first Roman emperor from 27 BC until his death in AD 14. The reign of Augustus initiated an imperial cult and an era of imperial peace (the Pax Romana or Pax Augusta) in which the Roman world was largely free of armed conflict. The Principate system of government was established during his reign and lasted until the Crisis of the Third Century.

Octavian was born into an equestrian branch of the plebeian gens Octavia. Following the assassination of Julius Caesar in 44 BC, Octavian was named in Caesar's will as his adopted son and heir, and inherited Caesar's name, estate, and the loyalty of his legions. He, Mark Antony, and Marcus Lepidus formed the Second Triumvirate to defeat the assassins of Caesar. Following their victory at the Battle of Philippi (42 BC), the Triumvirate divided the Roman Republic among themselves and ruled as de facto oligarchs. The Triumvirate was eventually torn apart by the competing ambitions of its members; Lepidus was exiled in 36 BC, and Antony was defeated by Octavian's naval commander Marcus Agrippa at the Battle of Actium in 31 BC. Antony and his wife Cleopatra, the Ptolemaic queen of Egypt, killed themselves during Octavian's invasion of Egypt, which then became a Roman province.