July 17

July 17 is the 199th day of the year, and the American record for it runs from 1821 to 1981 — a span of 160 years. The entry that anchors it: Harvard School of Dental Medicine is established in Boston, 1867.

The antebellum decades brought the date closer to the country’s central argument. In 1821, the Kingdom of Spain cedes the territory of Florida to the United States.

Reconstruction and the years that followed added their own entries. In 1867, Harvard School of Dental Medicine is established in Boston, Massachusetts. It is the first dental school in the U.S. that is affiliated with a university.

The early twentieth century brought industry, air travel and war to the date. In 1944, Port Chicago disaster — near the San Francisco Bay, two ships laden with ammunition for the war explode in Port Chicago, California, killing 320. A year later, in 1945, World War II — the main three leaders of the Allied nations, Winston Churchill, Harry S. Truman and Joseph Stalin, hold the Potsdam Conference in the German city of Potsdam to decide the future of a defeated Germany.

After 1945 the date reflects a country operating at global scale. In 1953, the largest number of United States midshipman casualties in a single event results from an aircraft crash in Florida, killing 44. Then, in 1968, Led by Ahmed Hassan al-Bakr, the Arab Socialist Ba'ath Party overthrew Iraqi president Abdul Rahman Arif in a bloodless coup. Seven years on, in 1975, Apollo–Soyuz Test Project — an American Apollo and a Soviet Soyuz spacecraft dock with each other in orbit marking the first such link-up between spacecraft from the two nations. Six years on, in 1981, a structural failure leads to the collapse of a walkway at the Hyatt Regency in Kansas City, Missouri, killing 114 people and injuring more than 200.

The date is also a birthday. Among the Americans born on July 17: Elbridge Gerry (1744), American merchant and politician, 5th Vice President of the United States; John Jacob Astor (1763), German-American businessman and philanthropist; John Wilbur (1774), American minister and theologian; Leander Clark (1823), American businessman, judge, and politician; and Ephraim Shay (1839), American engineer, invented the Shay locomotive.

July 17 is also a date of endings. Among the Americans who died on it: Jim Bridger (1881), American scout and explorer; William James Sidis (1944), American mathematician and anthropologist; Billie Holiday (1959), American singer; and Eugene Meyer (1959), American businessman and publisher.

What holds these 8 entries together is nothing more than the calendar, and nothing less. 160 years separate the earliest from the latest, and each was once simply the present day.