Complex sentence: In 1923, the newspaper was renamed "Arbeideren" ("The Worker"), and the first issue with this name was released on 1 May 1923, the International Workers' Day.
Split into simpler sentences: In 1923, the name had been changed to "Arbeideren" ("The Worker "). The first issue as"Arbeideren" came on 1 May 1923, the International Workers' Day.