Einstein accepted a temporary apprenticeship at the University of Bern in 1908. However, after two teaching semesters, he canceled his lectures because attendance had waned to just one student.
The following year, in 1909, Einstein was offered his first permanent academic position as a full professor at the University of Zurich. But he declined the offer, at first, because the pay was lower than his salary at the patent office.
It was only after the university raised their offer that Einstein accepted. "So, now I too am an official member of the guild of whores," Einstein wrote to a colleague, exclaiming the news.
Source: Einstein: His Life and Universe