Complex sentence: Born Crown Prince of Sweden, he retained his title and first place in succession for seven months until 1 January 1980 when he was stripped of both by a change in the Act of Succession to introduce absolute primogeniture.
Split into simpler sentences: Born Crown Prince of Sweden, he retained his title and first place in succession for seven months until 1 January 1980. On that date, he was stripped of both by a change in the Act of Succession to introduce absolute primogeniture.