(Bloomberg) — The mayor of western Hungary’s largest city, who was re-elected despite the publication of a video showing him participating in an orgy on a luxury yacht, has resigned less than a month after winning a fourth term.

Zsolt Borkai, the mayor of Gyor and a 1988 Olympic champion gymnast, said in an open letter on Wednesday that he was stepping down because of his “moral predicament.” His resignation is effective Friday. Under pressure, Borkai had already quit Prime Minister Viktor Orban’s ruling party last month.

Hungary’s opposition had seized on the Borkai scandal during the campaign for nationwide municipal elections as evidence of moral decay under Orban’s nine-year rule. The video was widely seen as having helped tip close races in favor of a united opposition, including in Budapest, and deal the Hungarian leader his worst electoral setback in more than a decade.