Olympique de Marseille, commonly referred to as OM or simply Marseille, is a professional football club based in the southern French city of Marseille. Founded in 1899 by René Dufaure de Montmirail, a young sports enthusiast who gathered like-minded students from Lycée Saint-Joseph and local workers to create a multi-sport organization with football being its flagship activity (source).
In its early years, the team was composed mostly of amateurs who combined their passion for football with day jobs. It didn't take long for OM's potential to be recognized - they won their first regional title in 1903 in the South-East Championship and quickly gained prominence both regionally and nationally (source).
One of the most notable matches during this period took place on March 5th, 1934 when OM faced FC Sète in the Coupe de France final. Although they lost that game (2-1), it marked an important milestone for the club as they were now considered serious contenders within French football (source).