The horizontal bar, as a gymnastic apparatus, was invented by the founder of the German gymnastic system Ludwig Jahn in 1811 and afterwards it was introduced and developed by him and his students. Jahn's primitive horizontal wooden bar was nothing more than a bar pinned-fixed between two trees. Later on, construct manufactured horizontal bars fixed on the ground, with two pilasters and with various arrangements and sizes. The exercises were mostly static, dynamic and close to the bar, since these wooden horizontal bars did not allow large swings. At the same time a special elaboration was established for the bar, in order to make it endurable and easy to use. In the middle of the 19th century the metal bars began to appear and influenced favourably the quality and the quantity of the exercises. At the same time this apparatus and the parallel bars were established as the dominant apparatuses of the German gymnastic system. The purpose of this study was to research and demonstrate the main features of the evolution of the horizontal bar (exercises, rules and apparatus) during the first half of the 19th century.