Karl Rokitansky (1804-1878) was the first to put forward a theory on pathogenesis of atherosclerosis. His "thrombogenic" theory is included in his famous three-volume Manual of Pathological Anatomy. In its first edition issued in 1844 he describes the disease under the heading Excessive formation of plaques on the interior of vessels. He does not use the term "atherosclerosis", speaking simply about a process. The description is merely macroscopic, based predominantly on lesions of the aorta. The process starts as thickening--hypertrophy and plaque formation of the vascular inner layer. The apposed pseudomembrane is composed of foreign substance of blood origin--fibrin. The pseudomembrane eventually develops into either an atheromatous process or ossification. Rokitansky accurately describes an atheromatous plaque with its lipid-rich interior, including its complications, however, he misregards plaque calcification for ossification. Although Rokitansky is aware that the disease may cause both narrowing and dilatation of a vessel, he claims that outcomes of the disease are unknown. In the third edition of Rokitansky's textbook issued 12 years later there are already included histological drawings of the aortic intimal and medial lesions.