Throughout the twentieth century, the Eroica Symphony – especially its opening Allegro con brio – attracted considerable interest from music scholars, especially theorists and analysts. This chapter surveys attempts to understand the movement as an organic whole, but it also explores several specific issues that were regularly aired during that period: ‘1’ the location of a ‘second subject’ within the exposition; ‘2’ the so-called ‘new theme’ in the development and its possible relationship to earlier themes; ‘3’ the horn player’s purportedly mis-timed entry at the end of the development, and its consequences for the start of the recapitulation; ‘4’ the status of the unusually long final section of the movement ‘is it simply an extended coda, or does it embrace a secondary development section?’; and ‘5’ the possible thematic significance of the two introductory chords.