Heinrich Eppendorf was a student of the humanities who stayed with Erasmus in Basel during 1522, perhaps remaining as long as early 1523. During his time there he served as Erasmus’ personal secretary and earned Erasmus’ trust; in a letter to Duke George of Saxony dated May 25, 1522, Erasmus wrote: “My one comfort in these great troubles is Heinrich Eppendorf, a young man both scholarly and civilized, whose character attests his noble birth. He has been in Basel now some months, where he is popular with every man of any judgement.” It is obvious from these words that Erasmus had spent considerable time with Eppendorf. This in turn implies that Erasmus brought him into his household; it was common practice in those days for men of substance to retain a large group of assistants and servants in his household, and we know that Erasmus followed this practice. Thus, it is almost a certainty that Eppendorf was actually lodging at Erasmus’ house.
Erasmus seems to have regarded Eppendorf as his right-hand man during this period; he brought him along on an important visit to Constance. In November of 1522, Ulrich von Hutten (who had previously befriended Erasmus) came to Basel to see him; however, Erasmus did not want to see Hutten, who had gained a rather unsavory reputation. Any association with Hutten would thus be detrimental to Erasmus’ reputation. At the same time, Erasmus did not want to hurt Hutten’s feelings. He entrusted the delicate diplomatic task of deflecting Hutten to Eppendorf, another indication of his trust in Eppendorf.
Eppendorf successfully completed his mission, but Hutten was outraged at what he considered to be ill-treatment, and made a bit of a stink about it. At the same time, Eppendorf’s attitude towards Erasmus darkened, and the two men parted ways in some anger. Thus began a strange and ugly episode in Erasmus’ life. Basically, he engaged in a public feud with Eppendorf that lasted for nine years. Why Erasmus, one of the most famous men in Europe, would bother to feud with a nobody like Eppendorf, remains a mystery. At first glance, one is tempted to suggest that he had engaged in homosexual activity with Eppendorf and was thus stung by what he considers to be Eppendorf’s betrayal. However, Erasmus had seen a steady stream of young humanists through his household, providing what we might now think of as postdoctoral studies to the best students in Europe. If he truly was in the habit of using these young men as sexual partners (a practice common in northern Italy at that time), then by 1530 Europe would have been peppered with such fellows, and it would have been impossible for a highly controversial figure such as Erasmus to have kept his secret.
But there’s even stronger evidence here. The following year, Hutten and Eppendorf, who were both deeply in debt, attempted to blackmail Erasmus. They wrote a scurrilous book that ferociously attacked Erasmus’s work. Then they sent a copy of the manuscript to Erasmus, warning him that, unless he paid them off, they’d publish it. Erasmus refused to be blackmailed and they proceeded to publish the manuscript. Here’s the crucial factor: the book makes no accusations that Erasmus was gay. It trashes him in many ways, but it doesn’t include that accusation – which would have been truly devastating to Erasmus’ reputation.
Thus, we have a situation in which a man who was intimately familiar with Erasmus and his household for nearly a year, who desperately needed money and attempted to blackmail Erasmus by publishing slanders about him failed to accuse him of homosexual behavior. This strikes me as compelling evidence that Erasmus was not gay.