This article proposes an exercise of intellectual history, seeking to find, on the book Panorama do teatro brasileiro [Brazilian theater overview], by Sabato Magaldi, some explanatory keys to the creation of a "founding mark" to the modern Brazilian theater, which had spread broadly in the intellectual environment of theatrical studies: the debut of Vestido de noiva [The wedding dress], by Nelson Rodrigues, in 1943. Thus, the main references that guide the reflection of Sabato will be analyzed, as well as the central devices that he builds for his writing of the Brazilian theatrical history. In the end of the text, a reflection about the challenges that theater historians face on the appearance of new theoretical perspective that destabilize the notion of "canon" is done and the big narratives that cover long historical periods.