The invention of the chronometer is generally attributed to John Harrison, a British clockmaker, in the 18th century.

Here's a breakdown:

* 1735: Harrison built his first marine timekeeper, which was significantly more accurate than existing timepieces.

* 1761-1762: Harrison presented his fourth and most accurate marine chronometer, H4, which won him the Longitude Prize.

While Harrison's work was groundbreaking, it was not the first attempt at a marine chronometer. Other clockmakers were working on similar projects, but Harrison's efforts were ultimately the most successful in solving the longitude problem.