Here's why:
* Slow and Stateliness: French overtures typically began with a slow, majestic section in a major key. This section was often in a duple meter (like 2/4 or 4/4) and featured a clear and straightforward melody.
* Homophony: The music in this opening section was usually homophonic, meaning that the melody was accompanied by chords, with no independent counterpoint.
This opening section was known as the "Lentement" (slowly) or "Grave" (serious) movement. It set the stage for the dramatic and energetic middle section and the final return to the opening theme.