Complex sentence: Adams (2010), 8--9 Her first venture into international diplomacy came, still early in her marriage, a Florentine delegation requested her political influence in the Gian Galeazzo Visconti affair.
Split into simpler sentences: Adams (2010), 8--9 Her first venture into international diplomacy occurred when she was newly married. A delegation from Florence approached her hoping she would use her political influence for them in the Gian Galeazzo Visconti affair.