[1] He travelled around Europe in pursuit of medical training, eventually moving from his native Bohemia to Germany, France and then on to Bologna in Italy; Horký became a vocal supporter of Italian academic culture, and of the Bolognese republican government.

[2][3] A medical student, copyist, and amateur philosopher, Horký quickly became active in the academic scene of northern Italy in the early 17th century.

[4] In 1610, the year of the publication of Galileo's Sidereus nuncius (translatable to "Starry Messenger"), Horký was employed as a secretary and copyist to Giovanni Antonio Magini, an influential professor of mathematics at the University of Bologna.

Horký reported that both Magini and Massimo Caprara were unable to see evidence of Jupiter's satellites, and ascribed Galileo's findings to distortions or tricks of the glass.

[4][5] Throughout Bologna [Galileo] has a terrible reputation: he is losing his hair; all of his skin is devastated by the 'French disease'; his skull is ruined and his mind delirious; his optic nerves have been destroyed because he has observed the minutes and seconds around Jupiter with too much curiosity and presumptuousness.

He has lost his sight, hearing, taste, and touch; his hands suffer from chiragra as he has illicitly pilfered the treasure of philosophers and mathematicians; his heart suffers from palpitations because he has passed the celestial fable off to everyone; since he can no longer convince scholars and illustrious persons, his intestines have issued an unnatural tumor; and since he has wandered hither and yon, his feet show signs of gout.

Despite being deprived of Magini's financial support, his work—Brevissima Peregrinatio contra Nuncium sidereum—roughly translatable to "A very short journey against 'Starry Messenger'"—was published and distributed to notable astronomers across Europe.

The pamphlet was heavily inspired by two contradictory sources: astrological principles (then considered a sister school to astronomy, now confirmed as pseudoscience) and the works of Johannes Kepler.

[8][10] In his pamphlet, Horký argued that Galileo's discovery of the satellites of Jupiter (later confirmed to be the Galilean moons) and lunar mountains were provably false and misleading.

Horký implied that Galileo's lens making technique was flawed, and that this had led to him reading focal defects and distortions as astronomical bodies.

Specify, he cited Kepler's 1610 pamphlet Dissertatio cum Nuncio as having shown Galileo's observations of lunar mountains and satellites of Jupiter to be false.

[1][8][13] Horký's arguments in Peregrinatio were ultimately flawed; Galileo's telescopes had been tested by the government of Venice the year before, and were found to be more accurate than many of his Italian contemporaries.

[8][14] Horký was in contact with a cluster of Florentines – a Vallombrosan monk (Orazio Morandi), Francesco Sizzi (later famed for discovering the movement of sunspots), an anonymous secretary, and Lodovico delle Colombe (a prominent Aristotelian physicist who would later push for Galileo to be investigated for heresy) – that readily supported his work.