Complex sentence: It was acquired by Random House in 1960 and is now part of the Knopf Doubleday Publishing Group at Random House, which has been owned since 1998 by the German private media corporation Bertelsmann.
Split into simpler sentences: It was acquired by Random House in 1960 and is now part of the Knopf Doubleday Publishing Group at Random House. It has been owned since 1998 by the German private media corporation Bertelsmann.