On March 13th 1781 Frederick William Herschel observed a bizarre celestial body moving in the sky. Retrospectively, that astral body was not at all new at that point. It was observed by a number of astronomers since the end of 17th century (and maybe earlier). But they failed to find out its motion and catalogued it as a fixed star – each time a different one. On the other hand, Herschel realized it was moving, and catalogued it as a comet. That news of a new finding in the sky rapidly spread throughout Europe, and after some months the ‘Herschel’s comet’ was correctly recognized as a new planet, which will be named Uranus. The present paper assumes the event of the discovery of Uranus and the assessment of its planetary nature as a system of complicated, interrelated processes which involved a number of actors in the 17th-century astronomical community. In this framework, the role of the Dalmatian-born jesuit scientist Ruggiero G. Boscovich is emphasized and the meaning of this discovery is discussed as an example of his interest in theoretical research more than in observational science.