Short answers, pulled from the story.
Classical republicanism originated in the mid-2nd century BCE with Greek historian Polybius writing his Histories to explain Rome's rise. It describes a mixed constitution combining monarchy, aristocracy, and democracy to maintain stability while conquering territories.
Leonardo Bruni lived from 1370 to 1444 and served as Chancellor of Florence while asserting that republican governments made better men than monarchies. Hans Baron coined the term civic humanism to describe this Florentine revival in 1928 based on long-standing political struggles.
Niccolò Machiavelli wrote Discourses on Livy which examined medieval political relations rather than ancient models exclusively. His work marked a turning point toward modern thought about governance despite remaining less famous than The Prince.
Pasquale Paoli led Corsica through fifteen years of independent rule from 1755 to 1769 before France conquered the island. He established universal male suffrage and possibly female voting rights during his administration.
The Whig canon includes John Milton, James Harrington, and Algernon Sidney among its authoritative figures. Thomas Paine distributed Rights of Man with forty thousand copies sold in Ireland by November 1791.
Philip Pettit published Republicanism: A Theory of Freedom and Government in 2000 to redefine liberty as non-domination. Isaiah Berlin distinguished between positive liberty and negative freedom in Four Essays on Liberty from 1970 while Hannah Arendt explored civic humanism in The Human Condition published in 1958.