Complex sentence: Ridolfi's talkative nature would eventually cause him trouble, as he was not very discreet and trumpeted his plan all over Europe, thus proving the failure of the plot in Florence, he told Grand Duke Cosimo de Medici who immediately informed Elizabeth of the plot.
Split into simpler sentences: Ridolfi's talkative nature would eventually cause him trouble, as he was not very discreet and trumpeted his plan all over Europe. His boasting was partially responsible for the failure of the Ridolfi plot, as he told Grand Duke Cosimo de Medici who immediately informed Elizabeth of the plot.