The paper aims at questioning the conceptual connection between Schumpeter, Sombart and Wieser on entrepreneurship. Using Schumpeter to come back before Schumpeter, we show which views these authors share on the character of the entrepreneur, the role of the entrepreneurial function in the economic process and the evolution of that notion up until the stage of developed capitalism (Hochkapitalismus). Thus, the entrepreneur appears as a key-stone for building capitalism. Finally, we indeed sketch the spirit of entrepreneurship as it emerges from the entrepreneurial function.