When was the beginning of the National League?
On April 23, 2008, against the Colorado Rockies, the Cubs recorded the 10,000th regular-season win in their franchise's history dating back to the beginning of the National League in 1876. The Cubs reached the milestone with an overall National League record of 10,000-9,465. Chicago was only the second club in Major League Baseball history to attain this milestone, the first having been the San Francisco Giants in mid-season 2005. The Cubs, however, hold the mark for victories for a team in a single city. The Chicago club's 77–77 record in the National Association (1871, 1874–1875) is not included in MLB record keeping. Post-season series are also not included in the totals. To honor the milestone, the Cubs flew an extra white flag displaying "10,000" in blue, along with the customary "W" flag.