In the novel Faust's name is Heinrich as opposed to the historical Johann Georg Faust who reportedly lived and died in Staufen, not in Heidelberg.
In Faust II, the legend of Johann Faust (at least in a version of the 18th century, which came to Goethe's attention) already contained Faust's marriage with Helen and an encounter with an Emperor.
Johann Sebastian Bach | Johann Wolfgang von Goethe | Faust | Johann Strauss II | St. Johann in Tirol | Georg Solti | Johann Heinrich Pestalozzi | Faust (opera) | Johann Albert Fabricius | Georg Philipp Telemann | Johann Christian Bach | Goethe's Faust | Johann Georg Wagler | Georg Wilhelm Friedrich Hegel | Johann Pachelbel | Johann Nepomuk Hummel | Johann Gottfried Herder | Georg Trakl | Georg Forster | Johann Nestroy | Georg Cantor | Georg Büchner | Georg Baselitz | Johann Joachim Winckelmann | Johann Gottlieb Fichte | Johann Bernhard Fischer von Erlach | Hans-Georg Backhaus | Johann Homann | Johann Friedrich Böttger | Georg von Holtzbrinck Publishing Group |
Johann Georg Faust (c. 1460–1540), widely considered to be an inspiration for the character of Faust