The first prominent baseball cards, called Old Judge, were first issued in 1887.
Notes on verification
Majority of credible sources (PSA, Library of Congress, Dean's Cards) confirm 1887 as the start year for Old Judge cards, though a couple of minor sources cite 1886. [tier=gold indep_score=0.867 clusters=3 claim_tier=notable]
Sources
- Would Baseball have Become America's National Pastime Without ... (seed:culture_and_philosophy)
- https://www.psacard.com/cardfacts/baseball-cards/1887-old-judge-n172/111 (corroboration)
- https://www.loc.gov/collections/baseball-cards/articles-and-essays/baseball-cards-1887-1914-card-sets-in-chronological-order/ (corroboration)
- https://www.deanscards.com/c/2913/1887-90-N172-Old-Judge (corroboration)