When examining the chronological establishment of Chicago's two major league baseball teams, the Chicago Cubs are the older franchise by a margin of several decades. The baseball club that evolved into the Cubs was founded in the 1870s and became a charter member of the National League in 1876, making them one of the oldest continuously operating professional sports organizations in North America. Meanwhile, the Chicago White Sox were established later as part of the formation of the American League at the turn of the twentieth century. This historical gap establishes the Cubs' definitive seniority in the city's rich baseball timeline.