Final answer:
The French names for the days of the week are derived from Roman gods and celestial bodies, with Sunday and Saturday being exceptions due to religious origins.
Step-by-step explanation:
The names of the days of the week in French and other Latin-based languages are derived from Roman gods and celestial bodies. Sunday (dimanche), however, doesn't follow this pattern in French, likely due to religious influence substituting the pagan deity with a reference to the Lord's day. Monday (lundi) is named after the Moon. The remaining days are named after Roman gods and associated planets: Tuesday is Mardi, after Mars; Wednesday is Mercredi, after Mercury; Thursday is Jeudi, after Jupiter; and Friday is Vendredi, after Venus. Saturday (samedi) derives from the Latin 'Sabbatum', which is related to the Sabbath, a day of rest.
Understanding these origins enriches comprehension of both language and cultural history. The calendar used today, known as the Gregorian calendar, has gone through several reforms to correct for discrepancies between the lunar and solar cycles.