Continuing attached to the University of Jena, where the dignity of Professorship was associated with that of Member of the Council, he now commenced a course of lectures on Aesthetics, and joined his brother Frederick in the editorship of the _Athenaeum_, (3 vols., Berlin, 1796-1800,) an Aesthetico-critical journal, intended, while observing a rigorous but an impartial spirit of criticism, to discover and foster every grain of a truly vital development of mind. It was also during his residence at Jena that he published the first edition of his Poems, among which the religious pieces and the Sonnets on Art were greatly admired and had many imitators. To the latter years of his residence at Jena, which may be called the political portion of Schlegel's literary career, belongs the _Gate of Honour for the Stage-President Von-Kotzebue_, (_Ehrenpforte fur den Theater Präsidenten von Kotzebue_, 1800,) an ill-natured and much- censured satire in reply to Kotzebue's attack, entitled the _Hyperborean Ass_ (_Hyperboreischen Esee_). At this time he also collected several of his own and brother Frederick's earlier and occasional contributions to various periodicals, and these, together with the hitherto unpublished dissertations on Bürger's works, make up the _Characteristiken u Kritiken_ (2 vols., Koenigsberg, 1801). Shortly afterwards he undertook with Tieck the editorship of _Musen-Almanack_ for 1802. The two brothers were now leading a truly scientific and poetic life, associating and co-operating with many minds of a kindred spirit, who gathered round Tieck and Novalis as their centre. His marriage with the daughter of Michaelis was not a happy one, and was quickly followed by a separation, upon which Schlegel proceeded to Berlin. In this city, towards the end of 1802, he delivered his _Lectures on the Present State of Literature and the Fine Arts_, which were afterwards printed in the _Europa_, under his brother's editorship. The publication in 1803 of his _Ion_, a drama in imitation of the ancients, but as a composition unmarked by any peculiar display of vigour, led to an interesting argument between himself, Bernhardi, and Schilling. This discussion, which extended from its original subject to Euripides and Dramatic Representation in general, was carried on in the _Journal for the Polite World_ (_Zeitung fur die elegante Welt_,) which Schlegel supported by his advice and contributions. In this periodical he also entered the lists in opposition to Kotzebue and Merkel in the _Freimüthige_ (_The Liberal_), and the merits of the so-called modern school and its leaders, was the subject of a paper war, waged with the bitterest acrimony of controversy, which did not scruple to employ the sharpest weapons of personal abuse and ridicule.