Arcadia of My Youth (わが青春のアルカディア, Waga Seishun no Arukadia) is an anime film depicting the origin of Leiji Matsumoto's seminal character Captain Harlock. At one time, it was considered to be the central hub of the so-called Leijiverse with the events depicted in other works such as Galaxy Express 999 and 1978's Space Pirate Captain Harlock television series occurring sometime after. It is directed by Tomoharu Katsumata, with Kazuo Komatsubara as animation director.

References:
https://en.wikipedia.org/wiki/Arcadia_of_My_Youth