Yehuda Elkana writes in Sign and Sight:
Einstein was a Freigeist, and his self-appointed, conscious task was to be a liberator –- a Befreier. In this he continued a great German cultural tradition established by Kant, Goethe, and simultaneously with Einstein, by Ernst Cassirer.
Einstein was a Befreier from all conventions, constraints, limitations – from everything that might be in the way of a free rein of the imagination (Fantasie).
Einstein’s all-important five papers, all written in the period of a few months in 1905, while he was a clerk in the patent office in Bern, and thus not part of a university, were the first clear demonstration of using his unfettered imagination.