In 1788 he published the first part of his _History of the Rebellion of the Netherlands_, which brought him the appointment to the chair of history in the University of Jena. The occupation with his next historical work, the _History of the Thirty Years' War_, suggested to him the thought of dramatizing the career of Wallenstein. But he was not yet clear with himself on questions of artistic method. He was studying Homer and dramatizing Euripides, lecturing and writing on dramatic theory. Further delays were due to marriage and to serious illness. It was not until 1796 that Schiller felt ready to begin work on the long planned drama of _Wallenstein_.
The first scenes were written in prose, but soon the poet realized that only the dignified heroic verse was suited to his theme. Then "all went better." Constant discussions with Goethe and Christian Gottfried Koerner helped him to clear up his doubts and overcome the difficulties of his subject. He found that history left too little room for sympathy with Wallenstein, for he conceived him as really guilty of treason. He decided early to lighten the gloom of his theme by introducing the love episode of Max and Thekla. He modified also his view of the nature of Wallenstein's guilt. Gradually the material grew upon him. What he had planned as a Prologue became the one-act play, _Wallenstein's Camp_, which, when it was produced in October, 1798, at the reopening of the Weimar Theatre, was preceded by 138 lines of Dedication, since printed as the _Prologue_. Already Schiller had foreseen the development into more than five acts, and accordingly _The Piccolomini_ appeared separately, January 30, 1799, and the whole series in order about the middle of April, upon the completion of _Wallenstein's Death_.
_Wallenstein_ is a trilogy, but in name rather than in real connection and relation of parts. _Wallenstein's Camp_ is a picture of masses, introducing only common soldiers and none of the chief personages of the other parts of the composition. Its purpose is to present something of the tremendous background of the action proper and to give a realizing sense of the influence upon Wallenstein's career of the soldiery with which he operated--as Schiller expressed it in a line of his Prologue: "His camp alone explains to us his crime." By this he meant that, on the one hand, the blind confidence of the troops in the luck and the destiny of their leader made him arrogant and reckless, and, on the other hand, perhaps, that the mercenary character of these soldiers of fortune forced Wallenstein to steps which his calm judgment would have condemned.