Short answers, pulled from the story.
The traditional founding of the Roman Republic and the consulship occurred in 509 BC. Ancient writers claimed the title came from the Latin verb consulere meaning to take counsel though the true origin likely lies in words suggesting get together or sit down together.
Inside Rome's walls twelve lictors accompanied every public appearance carrying fasces bundles that contained an axe symbolizing military power known as imperium. Outside city limits consuls held full imperium allowing them to punish soldiers or allies freely while citizens could not be executed without trial within the pomerium boundary.
Lucius Sextius became the first plebeian consul in 366 BC following the Licinio-Sextian rogations that opened the office partially to non-patricians. Before this year only patricians could hold the office until about fifteen novi homines gained election including Cicero who won in 63 BC.
Roman years customarily named after serving consuls like regnal years in monarchies with examples such as the year 59 BC called consulship of Caesar and Bibulus. Date ranges shifted multiple times throughout history starting September 1st before changing to January 1st by 153 BC and from 222 BC to 153 BC consuls took office March 15th due to Second Celtiberian War.
Western consulship ended in 534 with Decius Paulinus as final holder while Eastern consulship concluded in 541 under Anicius Faustus Albinus Basilius. Emperor Leo the Wise finally eliminated the office in Novel 94 of his Basilika during the late ninth century making Greek titles hypatos and apo hypaton lowly honorary dignities by that time.