I know there was an issue about reign years here, but the encyclopedia unfortunately doesn't clear it up, this is all it has to say about Josef I's reign:
帝国暦331(640)年第21代ゴールデンパウム王朝皇帝として即位。- He took the throne as the 21st Goldenbaum Kaiser in Imperial Year 331 (640).64.238.181.72 16:34, April 27, 2010 (UTC)