Here's why:
* Season 1 (1999): While critically acclaimed, the show had relatively low viewership.
* Season 2 (1999): The show's popularity exploded with the introduction of iconic characters like Tony's mother, Livia, and the memorable "Pine Barrens" episode.
* Critical Acclaim: By this point, the show had become critically lauded and garnered significant awards attention, further boosting its popularity.
Therefore, although the first season of The Sopranos premiered in 1999, it was its second season that truly propelled the show into mainstream popularity.