Short answers, pulled from the story.
Rosso Fiorentino was an Italian Mannerist painter born in Florence on the 8th of March 1495. He trained under Andrea del Sarto alongside Pontormo and later became one of the founding figures of the First School of Fontainebleau at the court of Francis I in France. His work is significant for its emotionally intense, contorted figures and its influence on French court art.
Rosso Fiorentino's masterpiece is generally considered to be the Deposition, also called the Descent from the Cross, an altarpiece housed in the Pinacoteca Comunale di Volterra. It was initially painted for the Duomo of Volterra and is distinguished by its sense of urgency, precarious figures on three ladders, and somber sky.
Rosso Fiorentino fled Rome following the Sacking of 1527, which scattered many artists. He eventually made his way to France and by 1530 had secured a position at the court of Francis I, where he worked at the Chateau Fontainebleau until his death in 1540.
Rosso Fiorentino died on the 14th of November 1540. Giorgio Vasari recorded that he died by suicide, but that claim has never been corroborated and is considered unsubstantiated by historians.
Works by Rosso Fiorentino are held at the Pinacoteca Comunale di Volterra, the Uffizi in Florence, and the Walters Art Gallery in Baltimore. A second Deposition altarpiece is in the church of San Lorenzo in Sansepolcro.
The First School of Fontainebleau was a group of artists who worked at the Chateau Fontainebleau under the patronage of Francis I of France. Rosso Fiorentino and Francesco Primaticcio were its two leading figures, bringing Italian Mannerist techniques in oil and fresco to French court decoration.