Short answers, pulled from the story.
The Florentine people rebelled in 1115 following the death of Matilda of Tuscany. This uprising marked the beginning of a new political era for the city and allowed them to assert their independence after Rabodo died during a dispute with the city.
Florence introduced the florin in 1252 as a gold currency with reliable fixed gold content. It became one of the common currencies of Europe and the Near East and was the first European gold coin struck in sufficient quantities to play a significant commercial role since the 7th century.
The Guelphs and the Ghibellines went to war in 1216 destroying the precarious peace at the beginning of the century. The Ghibellines supported noble rulers while the Guelphs were populists who eventually ruled the city from 1250 until their defeat at the Battle of Montaperti in 1260.
Cosimo de Medici returned to Florence less than a year after his exile began following a democratic vote by the Florentine people. He had been exiled in 1433 but returned to acclaim while the Albizzi family faced banishment.
Florentine authorities executed Savonarola by burning him at the stake in the Piazza della Signoria in May 1498. People blamed him for food shortages and isolated cases of plague that followed a failed war with Pisa which led to his execution after years of influence over the state's direction.
The republic ended in 1569 when Cosimo was elevated to Grand Duke of Tuscany by Pope Pius V marking the beginning of hereditary monarchy. This occurred after the surrender of the Republic during the Siege of Florence on the 12th of August 1530 when Emperor Charles V issued a proclamation stating he alone could determine the government.