In the following text the author makes an analogue between the modulation theories of Hugo Riemann and Parashkev Hadjiev as representatives of two different schools of harmony, as well as their different positions concerning the fundamental connection: modulation - musical form, with the focus on Riemann's 'Systematische Modulationslehre als Gmndlage der musikalischen Formenlehre' ('Harmony Simpliüed orthe Theory ofthe Tonal Functions of Chords.') According to Riemann, modulation is no more than functional interpretation (Umdeutung der Funktionen) in the meaning of a new explication, or change of functional meaning, while in Parashkev Hadjiev modulation is a transition to the new; it is fully formed and established with a cadential tonality. For Riemann the genesis of large forms is in small structures, i.e., cadences. Thus, according to Riemann, the difference between intermediate cadences and modulation is only in size but not in content. In a static tonal center as tonic, different tonalities appear only as different levels of extended harmony according to their functional meaning, in Riemann's terminology. The author follows different harmonic phenomena in the meaning of potential or real modulation as: cadence and its different forms of extensions (for example, using intermediate dominants and pedal points), tonal jumps (Tonalitätssprünge) and modulation. The text takes into account the differences with our harmony school - for example, the so-called (Rückgang) in Riemann, which returns us to the original tonality.