September 7, 1947 : H. Clay Earles opens Martinsville Speedway as a dirt track with 750 seats and a paid crowd of 6,013. Red Byron wins the 50-lap feature for "Modified Stock Cars” and earns $500 out of a $2,000 purse.
July 4, 1948 : Martinsville runs its first race under a NASCAR sanction, with Fonty Flock winning the feature followed by Pee Wee Martin of Bassett. Va., Buck Baker, Bill Blair, and Tim Flock as 4,000 watched. Bill France finishes eighth while one of those sidelined with mechanical problems is 19-year-old Fireball Roberts.
September 25, 1949 : NASCAR's "Strictly Stock" division, now the Sprint Cup Series, makes its first appearance at the speedway and Byron wins again in an Oldsmobile 88 with Lee Petty second in a 1949 Plymouth. Seating increased to 10,000.
1950 : The speedway starts running two NASCAR Grand National (Sprint Cup) events races a year on the dirt track. The Strictly Stock Series was renamed the Grand National Series that year.