Georg Joachim Rheticus could have been Copernicus' successor, but did not rise to the occasion.[58] Erasmus Reinhold could have been his successor, but died prematurely.[58] The first of the great successors was Tycho Brahe[58] (though he did not think the earth orbited the sun), followed by Johannes Kepler,[58] who had worked as Tycho's assistant in Prague.[citation needed]