Text: The Princes' Chapel (Cappella dei Principi) is a piece of 17th-century Baroque bombast in flamboyant multi-colored marbles, for which the altar was not completed, appropriately enough, until 1939.
Entailment: The Cappella dei Principi's altar took around 300 years to finish.
Contradiction: The Cappella dei Principi was finally completed in 1945.