55 Julius Caesar commands the first Roman invasion of Britain. Due to bad weather and revolts in Gaul the expedition achieves little, but the Roman Senate decrees twenty days of thanksgiving.
49 The Roman Senate receives a proposal from Julius Caesar that he and Pompey should lay down their commands simultaneously. The Senate responds that Caesar must immediately surrender his command.
49 Julius Caesar leads his army across the Rubicon, which separates his jurisdiction (Cisalpine Gaul) from that of the Senate (Italy), and thus initiates a civil war. In response, the Roman senate invokes the ''senatus consultum ultimum''.
49 Pompey's flight to Epirus (in Western Greece) with most of the Senate.
32 The Roman Senate declares war upon Marc Antony and Cleopatra; Caesar Augustus is proclaimed dux and the West swears an oath of loyalty to him. In order to assure this oath, Octavian publishes what is purported to be Antony's will and which bequeaths all Eastern lands to Cleopatra.
27 The Roman Senate votes Octavian the title of '''Augustus'''. He accepts this honor, having declined the alternative title of '''Romulus'''. He is known as Augustus afterwards.
15 In Rome, the selection of civil servants passes from the people to the Emperor and the Senate.
23 Aelius Sejanus begins to dominate the Roman Senate and Tiberius, after the death of Julius Caesar Drusus.
37 Caligula's attempt to have himself deified creates friction between himself and the Senate
37 The Roman Senate annuls Tiberius' will and proclaims Caligula Roman Emperor.
41 After a night of negotiation, Claudius is accepted as Emperor by the Senate.
45 The Senate hold consultations regarding real estate speculation in Rome
48 Gallic nobles are admitted to the Roman Senate. Claudius grants the rights of citizenship to the Aedui.
49 Agrippina charges Octavia's first fianc
53 Claudius secures a Senatorial decree which gives jurisdiction in financial cases to imperial procurators. This marked a significant strengthening of imperial powers at the expense of the Senate.
57 Envoys from Cilicia come to Rome to accuse their late governor, Cossutianus Captio, of extortion; the Roman Senate is supported in the case by Publius Clodius Thrasea Paetus.
59 Publius Clodius Thrasea Paetus retires from the Roman Senate.
68 The Roman Senate declares Nero ''persona non grata''. Galba succeeds Nero.
68 The Roman Senate accepts emperor Galba.
79 To please the Senate, Titus exiles his Jewish mistress, Berni
80 The first African enters the Roman Senate.
85 Domitian appoints himself censor for life, which gives him the right to control the Senate. His totalitarian tendencies put the senatorial aristocracy firmly in opposition to him.
94 Domitian rebuilds and rededicates the Curia Julia (meeting place of the Roman Senate), which had burned down in 64.
96 Under Nerva, the Roman Senate regains much of the power usurped by Domitian.
118 Plot of the consuls: Hadrian executes four senators, all former consuls, who had been shown to have plotted against him. His relations with the Senate are strained.
131 Under the reorganisation, the Roman Senate is excluded from controlling the business of state.
136 The war against the Suebi begins. They will be defeated by the senator Tiberius Haterius Nepos Atinas, governor of Pannonia in 138
138 On Hadrian's death, the Senate, which had been stripped of power during his reign refuses to deify him. Some speak of declaring him a tyrant cancelling his acts.
161 Marcus Aurelius, a Spaniard like Trajan and Hadrian, is a stoical, disciple of Epictetus, and an energetic man of action. He pursues the policy of his predecessor and maintains good relations with the Senate. As a legislator, he endeavours to create new principles of morality and humanity, particularly favouring women and slaves.
183 Failed assassination attempt on Roman Emperor Commodus by members of the Senate.
195 Emperor Septimius Severus has the Senate deify Commodus in an attempt to gain favor with the family of Marcus Aurelius.
197 Sixty-four senators are denounced as accomplices of Albinus and twenty-four are put to death.
211 Septimus Severus dies in Britain, and is later deified by the Senate
222 Alexander Severus succeeds Elagabalus. However, as he is only 13 years-old, his Aunt, Julia Maesa, governs the empire with the help of Domitius Ulpianus and a council composed of senators.
238 The town of Aquileia takes the side of Roman Senate against Maximinus Thrax.
357 Constantius enters Rome for the first time to celebrate his victory over Magnentius and to address the Senate and the people of Rome.
375 Gratian, advised by Ambrose, begins a systematic persecution of the pagans. He confiscates the fortunes of the temples and adds the money to the Imperial Treasury, and removes the Altar of Victory from the Senate. He proscribes Arianism and Donatism.
381 A deputation from the Roman Senate delivers to Gratianus the robe of the Pontifex Maximus, which had been worn by every Roman Emperor since Augustus. He refuses to accept this insignia, insulting the pagan aristocrats of Rome.
409 Visigothic King Alaric I lays siege to Rome a second time; with agreement of the Senate he sets up Priscus Attalus as western emperor
580 The Roman Senate sends an embassy to Constantinople; this is its last recorded act.