Tkadlík used Sketchbook C during his stay in Vienna and the oldest drawings date back approximately to 1817 and 1818. The initial landscape sketches that most probably came into existence during outings to environs of Vienna are distinguished by their excellent handling. These drawings differ significantly from the Bohemian and Saxon Switzerland sketches - in them, Tkadlík works with washes in large areas, which simultaneously give the impression of three-dimensionality and planarity and contribute to a sense of certain detachment, abstractedness. It is especially noticeable in the treatment of architecture in which he focuses on linear drawing of sharply defined forms that are reduced to geometrical shapes. The majority of figural studies continue to reflect the Classical works that formed the background for his academic training. There are many drawings made according to Raphael and works of antiquity. Through an examination of the sketchbook, it is possible to trace Tkadlík’s ongoing and quite profound interest in biblical and broader religious themes. The Sketchbook C includes studies of the attire worn by a Jewish High Priest and a Greek monk completed using an as-of-yet unidentified French source. It was during this time that Tkadlík created several religious compositions. The studies for some of them, such as Jesus in Emmaus, St. Joseph and the Christ Child, and Rest on the Flight into Egypt, are also found in Sketchbook C. It is however obvious that Tkadlík’s interest was not concentrated merely on the external aspects of costumes and ceremonial objects. The copious notes associated with the drawings, including citations in Latin, provide evidence of how deeply immersed he was in this topic, as well as of the fact that he was one of the most educated Czech artists of his time. Orientalism was another topic popular at the time and it is also addressed in Tkadlík's sketchbooks. Three sequential sheets in Sketchbook C contain studies of a woman in Oriental costume, a preliminary sketch for a composition, and two sketches of Oriental figures.