As a leader of this revived democracy in the 4th century BC, Thrasybulus advocated a policy of resistance to Sparta and sought to restore Athens' imperial power.

Several facts make it clear that he was from a wealthy family; he held the office of trierarch,[3] which involved significant personal expenditures on several occasions, and in the 4th century BC his son was able to pay a substantial fine of 10 talents.

Seeking to contain the crisis, Athens tapped its reserve fund to rebuild its fleet and dispatched what ships it had to establish an advance naval base at Samos.

Donald Kagan has suggested that Thrasybulus was one of the founding members of the scheme and was willing to support moderate oligarchy, but was alienated by the extreme actions taken by the plotters.

Samian democrats learned of the conspiracy and notified four prominent Athenians, the generals Leon and Diomedon, Thrasybulus, and Thrasyllus, at that time a hoplite in the ranks.

With the support of these men and the Athenian soldiers and sailors in general, the Samian democrats were able to defeat the conspirators when they attempted to seize power.

[12] Shortly after this, following the revolt of Euboea, the government of the 400 at Athens was overthrown and replaced by a broader oligarchy, which would eventually give way to democracy.

This operation was thwarted, however, by a sudden storm which drove the rescue force to land, and a great number of Athenians—estimates as to the precise figure have ranged from near 1,000 to as many as 5,000—drowned.

[citation needed] Five days later, Thrasybulus led his force, which had already grown to the point that he could leave 200 men at Phyle while taking 1,000 with him, to Piraeus, the port of Athens.

[21] In the revived democracy established in 403 BC, Thrasybulus became a major and prestigious leader, although he was soon superseded at the head of the state by Archinus.

Thrasybulus seems to have advocated a more radically democratic policy than the populace was willing to accept at the time; he called for reinstating pay for political service, and sought to extend citizenship to all the metics and foreigners who had fought alongside him against the Thirty.

He was initially cautious about offending Sparta, but, when Persian support became available at the start of the Corinthian War, he became an advocate of aggressive action, and about this time seems to have regained his preeminence in Athenian politics.

Thrasybulus, leading the faction that sought to reject the peace offer, regained his position atop Athenian politics.

In 389 BC, he led a force of triremes to levy tribute from cities around the Aegean and support Rhodes, where a democratic government was struggling against Sparta.

On this campaign, Thrasybulus relaid much of the framework for an Athenian empire on 5th century BC model; he captured Byzantium, imposed a duty on ships passing through the Hellespont, and collected tribute from many of the islands of the Aegean.

Most of the major ancient historians assigned credit for the dramatic Athenian victories of 411 BC to Alcibiades, but a few, such as Cornelius Nepos, pointed to the decisive role that was played in these battles by Thrasybulus.

More recent historians, such as Donald Kagan and R. J. Buck, have tended to support this analysis, pointing to the role that Thrasybulus played in crafting Athenian strategy in all these battles, and specifically to the decisive action he took at Cyzicus, which saved Alcibiades's force from being swamped, and turned a potential Athenian defeat into a stunning victory.

[28][29] R. J. Buck has suggested that Thrasybulus suffered from an "anti-democratic tradition of ancient historiography," which led many writers to minimize the accomplishments of one of democracy's strongest advocates.

In the words of Cornelius Nepos, This most noble action, then, is entirely Thrasybulus's; for when the Thirty Tyrants, appointed by the Lacedaemonians, kept Athens oppressed in a state of slavery, and had partly banished from their country, and partly put to death, a great number of the citizens whom fortune had spared in the war, and had divided their confiscated property among themselves, he was not only the first, but the only man at the commencement, to declare war against them.

[21]John Fine points to the clemency shown by Thrasybulus and other democrats in the wake of their victory over the Thirty as a key contribution towards reestablishing stable government in Athens.

[31] The second-century travel writer Pausanias called Thrasybulus "the greatest of all famous Athenians" for overthrowing the Thirty as well as his other exploits, making clear that he thought him greater than even Pericles.

[33] R. J. Buck suggests that Thrasybulus, who came of age in the heady days when the democracy and empire under Pericles were at their fullest extent, never accepted that the devastating losses Athens had suffered in the Peloponnesian War made the return of those times impossible.

[citation needed] Buck has compared him to Winston Churchill, another advocate of imperial policies who held fast to his beliefs after the tide of history had turned against him, and who rose to his peak of prominence at his country's darkest hour.