There has never be anything quite like Renaissance Italy, and nothing I could make up would ever match it. Until now this series has admitted no historical characters later than 1241, but alert readers may have noticed a couple of notable Florentines managed to get themselves mentioned. They would both have been around town at the time, two stars in a galaxy of geniuses.
Longdirk's world is lagging a little behind ours. Mobile cannon were introduced into Italy by Charles VIII of France in 1494. Improvements in firearms soon made armored knights obsolete. The age of the great condottieri, which had begun with the (largely English) White Company in the mid-fourteenth century, ended with the death of Giovanni of the Black Bands in 1526.
In 1527 Florence drove out the Medici family for the third time. This was a serious error, because Pope Clement VII was a Medici, and he arranged for the Spanish army to bring the rebellious city to heel. The siege began in 1528 and lasted a year before starvation forced Florence to surrender. The man who extended the walls to enclose the hill of San Miniato was an engineer named Michelangelo Buonarroti; he also dabbled in sculpture, painting, architecture, and poetry.
Pietro Marradi is loosely based on Lorenzo de' Medici (who was not distinguished as Lorenzo the Magnificent until long after his death in 1492). Lucrezia is based not on Lucrezia Borgia, but on her public image. Personally I do not believe she had any part in the numerous poisonings attributed to her brother Cesare and their father Pope Alexander VI, nor that she bore an illegitimate child by either of them. Her daddy, however… They just don't make popes like him anymore.