The 1856 Republican National Convention was the first national nominating convention of the Republican Party, which had been founded two years before, and was held to nominate the party's candidates for president and vice president in the 1856 election. The convention selected former Senator John C. Frémont of California for president and former Senator William L. Dayton of New Jersey for vice president.

https://en.wikipedia.org/wiki/1856_Republican_National_Convention