The Medicis and the Borgias were two ruling families in Renaissance Florence and Rome respectively. Political intrigue in Renaissance Italy was legendary for its complexity and ruthlessness; the famously unscrupulous Machiavelli dedicated his notorious political manual, The Prince, to Lorenzo de Medici. Neither of these familes was above using extortion or violence to seize or hold on to power.
The Medicis were fond of white arsenic as a means of dispatching their enemies. Catherine de Medici (1519-1589), who married King Henry II of France, was known as 'Madame Snake' for her fondness for poisoned rings and hidden daggers. Ironically she was also known as a good cook, responsible for bringing fine Italian cuisine to France.
Arsenic was also the house poison of the Borgia dynasty in Rome. Their rule was particularly corrupt, even by Renaissance Italy's standards, and there is evidence that various Borgias indulged in murder, blackmail, theft, rape, and incest. Lucrezia Borgia (1480-1519) was rumoured to have a hollow ring from which she would drip poison into her victims' drinks. She is a distant relative of most of the Royal families in Europe, including that of Great Britain.