What was the only event at the inaugural Wimbledon Championship in 1877?

The only event at the inaugural Wimbledon Championship in 1877 was the Gentlemen's Singles.

The All England Croquet and Lawn Tennis Club staged the tournament after lawn tennis had been added to its activities. The club needed money to repair a pony roller used to maintain its grounds, so it organised an amateur lawn-tennis championship. No ladies’ singles, doubles or mixed-doubles competitions were included.

Twenty-two men entered, each paying one guinea. The tournament began on 9 July, but rain delayed the final until 19 July. Spencer Gore defeated William Marshall in three sets, 6–1, 6–2, 6–4, in a final lasting 48 minutes. About 200 spectators watched and paid one shilling each.

The event’s silver prize was the Field Cup, donated by the sports magazine The Field. The ladies’ singles and gentlemen’s doubles competitions were introduced in 1884, while ladies’ doubles and mixed doubles did not arrive until 1913. Thus, “Gentlemen’s Singles” refers to the sole competition, not merely the tournament’s headline event.