Study at the University
Erfurt, the commercial center of the fruitful Thuringian basin, lying at the intersection of major trade routes, was a populous city with its approximately 20,000 inhabitants.1 Ever since his student days Luther was very well aware of its commercial, social, political, and ecclesiastical position. He knew its excellent location: "Erfurt lies in the best spot; there a city would have to stand, even if it were immediately burned down." He considered it impregnable because of its fortifications. Since it appeared to him to be extraordinarily strong, he greatly overestimated the size of the population.2 Observing the fertility of the region as well, he called Erfurt a Bethlehem, a house of bread, or a grease pit (Schmalzgrube). He recalled that the production of wine flourished there, and that in good years there were problems of marketing. He quoted later from a sermon by the Erfurt theologian Sebastian Weimann: "God afflicts other people with high prices, but us he punishes with abundance."3 Quite profitable was the cultivation of Weid, a type of plant from which a desirable blue dye could be extracted. Luther was against the cultivation of Weid rather than grain, because he mistakenly believed that it would leach out the soil.4 It was probably in Erfurt that he became acquainted with the Scherf, a coin worth half a pfennig, which he immortalized in the German language by speaking in his Bible translation of the widow's Scherflein (tiny mite).
Erfurt was one of the larger cities in Germany. It governed eighty-nine villages, one of which, Kapellendorf, was even an imperial fief. In 1392 Erfurt had been able to establish a civic university. But as Luther also knew, it was unsuccessful in freeing itself from princely authority and becoming a free city.5 That was because the city lay in an area in which the interests of the archdiocese of Mainz and those of Saxony overlapped. Neither of these two powers would permit it to be independent. Erfurt had to identify itself in its coat of arms as a faithful daughter of Mainz, while Saxony acted as the protector of the city and held it in check by occasional trade blockades. In the second half of the fifteenth century Erfurt was unfortunately involved in the disputes over the archdiocese of Mainz between Adolf von Nassau and