A legatus (Classical Latin: [ɫeːˈɡaːtʊs]; anglicised as legate) was a high-ranking Roman military officer in the Roman Army, equivalent to a high-ranking general officer of modern times. Initially used to delegate power, the term became formalised under Augustus as the officer in command of a legion.
From the times of the Roman Republic, legates received large shares of the military's rewards at the end of a successful campaign. This made the position a lucrative one, so it could often attract even distinguished consuls or other high-ranking political figures within Roman politics (e.g., the consul Lucius Julius Caesar volunteered late in the Gallic Wars as a legate under his first cousin, Gaius Julius Caesar).
Roman Republic
The rank of legatus existed as early as the Samnite Wars, but it was not until 190 BC that it started to be standardized, meant to better manage the higher numbers of soldiers the Second Punic War had forced to recruit. The legatus of a Roman Republican army was essentially a supreme military tribune, drawn from among the senatorial class of Rome (usually a consul or proconsul),[1] who acted as a second-in-command to the magistrate in charge of the force.[2][3] This role was usually played by either seasoned generals or ambitious young senators; the latter option eventually displaced the military tribune as a path to gain recognition.[2][4]
The legatus was officially assigned by the Senate a group of people who made official decisions similar to the ruler, although it was generally only done after consulting with the magistrate in command,[2][3] hoping to pair a commander and a lieutenant who could work together without trouble. This was established to avoid clashes of leadership like that of the consuls Varo and Paulus in Cannae.[2] The legatus often acted as a military consultant or adviser, like Scipio Africanus did for his brother Lucius during the Roman–Seleucid War, or as a trusted man of action, as in the case of Lucius Quinctius Flamininus and his brother Titus in their campaigns.
https://en.wikipedia.org/wiki/Legatus
- - - - - - - - - - - - - - - - - - - - - - - - - - -
A papal legate or apostolic legate (from the ancient Roman title legatus) is a personal representative of the Pope to foreign nations, to some part other of the Catholic Church, or representatives of the state or monarchy. He is empowered on matters of Catholic faith and for the settlement of ecclesiastical matters.
The legate is appointed directly by the Pope—the Bishop of Rome and head of the Catholic Church. Hence a legate is usually sent to a government, a sovereign or to a large body of believers (such as a national church) or to take charge of a major religious effort, such as an ecumenical council, a crusade to the Holy Land, or even against aheresysuch as the Cathars.
Legatus natus
Literally "born legate", i.e. not nominated individually but ex officio, namely a bishop holding this rank as a privilege of his see, e.g. archbishops of Canterbury (pre-Reformation), Prague, Esztergom, Udine, Salzburg, Gniezno and Cologne.[7][8] The legatus natus would act as the Pope's representative in his province, with a legatus a latere only being sent in extraordinary circumstances. Although limited in their jurisdiction compared to legati a latere, a legatus natus was not subordinate to them.[9]
Legatus missus
Literally "sent legate", possessing limited powers for the purpose of completing a specific mission. This commission is normally focused in scope and of short duration.[7][8]
https://en.wikipedia.org/wiki/Papal_legate