An unknown part of Weierstraß's Nachlaß (Q1282321)

Karl Weierstraß was an exceptional mathematician who brought a significant contribution to the development of the science of mathematics; in spite of all these, he is almost unknown, even by specialists in the field. Although some people wrote a sketch of his biography (e.g., Gösta Mittag-Leffler and Wilhelm Lorey were the first), information on this topic is quite scarce. The chance to improve the situation occurred with the fortunate discovery of another part of Weierstraß's most important work, \textit{Nachlass}, in an archive in Merseburg in 1980. Mention is made also of a set of personal letters exchanged between Weierstraß and several of his colleagues (Kronecker, Heilermann, Paul du Bois-Reymond, Ferdinand Lindemann, Leo Koenigsberger, Ludwig Kiepert et al.).