Hipparchus, the brother of the tyrant Hippias, was killed by Harmodius and Aristogeiton, who were subsequently honored by the Athenians for their alleged restoration of Athenian freedom.

His brother Hipparchus, who may have ruled jointly with him, was murdered by Harmodius and Aristogeiton ( the Tyrannicides ) in 514 BC.

When Peisistratus died in 528 / 527 BC, his son Hippias, with the help of his younger brother Hipparchus, retained power.

His maternal grandmother with his father were sister and brother His maternal uncle Lucius Vibullius Hipparchus was an Archon of Athens in the years 99-100 and his maternal cousin, Publius Aelius Vibullius Rufus was an Archon of Athens between 143-144.

An important role in this standardisation appears to have been played by the Athenian tyrant Hipparchus, who reformed the recitation of Homeric poetry at the Panathenaic festival.

The tyrant Peisistratos had died in 527 BC, passing power to his sons, Hipparchus and Hippias.

Bacchylides's career as a poet probably benefitted from the high reputation of his uncle, Simonides, whose patrons, when Bacchylides was born, already included Hipparchus, tyrant of Athens 527 – 14 BC.

Ceos lies only some fifteen miles south-east of Attica, whither Simonides was drawn, about the age of thirty, by the lure of opportunities opening up at the court of the tyrant Hipparchus, a patron of the arts.

The murder of his son, the tyrant Hipparchus by Aristogeiton and Harmodios in Athens in 514 BC marked the beginning of the so-called " cult of the tyrannicides " ( i. e., of killers of tyrants ).

Modern scholarship generally ascribes the tradition that Hipparchus was himself a cruel tyrant to the cult of Harmodius and Aristogeiton established after the downfall of the tyranny.

They became known as the Tyrannicides ( τυραννοκτόνοι ) after they killed the Peisistratid tyrant Hipparchus, and were the preeminent symbol of democracy to ancient Athenians.

* Hipparchus ( son of Pisistratus ), an ancient Athenian tyrant

* Hipparchus of Euboea, an ancient Euboean tyrant

Hipparchus was murdered in 514 BC, and in response to this, Hippias became paranoid and started to rely increasingly on foreign mercenaries to keep a hold on power.

* 527 Pisistratus dies, succeeded by sons Hippias and Hipparchus

* 515 Hippias becomes sole ruler after the death of Hipparchus

Peisistratus ' sons Hippias and Hipparchus, on the other hand, were not such able rulers, and when the disaffected aristocrats Harmodios and Aristogeiton slew Hipparchus, Hippias ' rule quickly became oppressive, resulting in the expulsion of the Peisistratids in 510 BC, who resided henceforth in Persepolis as clients of the Persian Shahanshah ( King of kings ).

Both Hipparchus and Hippias enjoyed the popular support of the people.

Peisistratus died in 527 BC and was succeeded by his sons Hippias and Hipparchus.

This was an offense of such magnitude to Harmodius ' family that he, together with Aristogeiton who was already fired by feelings of jealousy due to Hipparchus having made unrequited sexual advances toward Harmodius ( possibly the motivation for Hipparchus's humiliation of Harmodius's sister ), resolved to assassinate both Hippias and Hipparchus and thus to overthrow the tyranny.

Distrusting tradition, he took a few of the finest dialogues as his standard, and from internal evidence denounced as spurious not only those generally admitted to be so ( Epinomis, Minos, Theages, Rivales, Clitophon, Hipparchus, Eryxias, Letters and Definitions ), but also the Meno, Euthydemus, Charmides, Lysis, Laches, First and Second Alcibiades, Hippias Major and Minor, Ion, Euthyphro, Apology, Crito, and even ( against Aristotle's explicit assertion ) The Laws.

His sons Hippias and Hipparchus succeeded him.

Greek historian Plutarch discusses an argument between Chrysippus ( 3rd century BCE ) and Hipparchus ( 2nd century BCE ) of a rather delicate enumerative problem, which was later shown to be related to Schröder numbers.

Hipparchus of Nicaea, or more correctly Hipparchos (; c. 190 BC – c. 120 BC ), was a Greek astronomer, geographer, and mathematician of the Hellenistic period.

Hipparchus was born in Nicaea, Bithynia ( now Iznik, Turkey ), and probably died on the island of Rhodes.

Although Greek astronomers had known, at least since Hipparchus, that the tropical year was a few minutes shorter than 365. 25 days, the calendar did not compensate for this difference.

It was not separated from Centaurus until Hipparchus of Bithynia named it Therion ( meaning beast ) in the 200s BCE.

A later developer in this tradition was Hipparchus.

A central problem was that of projectile motion, which was discussed by Hipparchus and Philoponus.

Taking a different view from other modern scholars, Ulansey argues that the Mithraic mysteries began in the Greco-Roman world as a religious response to the discovery by the Greek astronomer Hipparchus of the astronomical phenomenon of the precession of the equinoxes – a discovery that amounted to discovering that the entire cosmos was moving in a hitherto unknown way.

In discussing the work of Pytheas, Strabo typically uses direct discourse: " Pytheas says ..." In presenting his astronomical observations, he changes to indirect discourse: " Hipparchus says that Pytheas says ..." either because he never read Pytheas ' manuscript ( because it was not available to him ) or in deference to Hipparchus, who appears to have been the first to apply the Babylonian system of representing the sphere of the earth by 360 °.

The star catalog of Hipparchus ( 2nd century BC ) included 1020 stars and was used to assemble Ptolemy's star catalogue.

As another example, they specified that the mean synodic month was 29 ; 31, 50, 8, 20 days ( four fractional sexagesimal positions ), which was repeated by Hipparchus and Ptolemy sexagesimally, and is currently the mean synodic month of the Hebrew calendar, though restated as 29 days 12 hours 793 halakim ( where 1 hour = 1080 halakim ).

Ptolemy's catalogue was based almost entirely on an earlier one by Hipparchus ( Newton 1977 ; Rawlins 1982 ).

At the time, it was known as the Year of the Consulship of Torquatus and Hipparchus ( or, less frequently, year 896 Ab urbe condita ).

Although Strabo cited the antique Greek astronomers Eratosthenes and Hipparchus, acknowledging their astronomical and mathematical efforts towards geography, he claimed that a descriptive approach was more practical, such that his works were designed for statesmen who were more anthropologically than numerically concerned with the character of countries and regions.

It was later known to Hipparchus, Pliny and Ptolemy, but under different names.

Hipparchus concluded that the equinoxes were moving (" precessing ") through the zodiac, and that the rate of precession was not less than 1 ° in a century, in other words completing a full cycle in no more than 36000 years.

Similar claims have been made that precession was known in Ancient Egypt prior to the time of Hipparchus, but these remain controversial.

Using observations of the equinoxes and solstices, Hipparchus found that the length of the tropical year was 365 + 1 / 4 − 1 / 300 days, or 365. 24667 days ( Evans 1998, p. 209 ).

Hipparchus dropped one more day from four Callipic cycles ( 304 years ), creating the Hipparchic cycle with an average year of 365 + 1 / 4 − 1 / 304 or 365. 24671 days, which was close to his tropical year of 365 + 1 / 4 − 1 / 300 or 365. 24667 days.