1865 was year 2 of the Genji (元治) era, from 25 April 1864 to 22 June 1865, and year 1 of the Keio (慶応) era, from 23 June 1865 to 22 October 1868.
Convert a Japanese era date like Showa 14 into a Western year, or convert a Western year like 1964 into a Japanese era year.
See also the FAQ page on Japanese years and the FAQ complete list of Japanese eras.