Short answers, pulled from the story.
Ambrogio Lorenzetti is best known for The Allegory of Good and Bad Government, a cycle of frescoes painted in the Sala dei Nove of Siena's Palazzo Pubblico. The well-preserved panel depicting a well-governed town and countryside is considered an unrivaled pictorial record of life in a peaceful medieval settlement. He is also credited with early experiments in linear perspective and physiognomy that anticipate the Italian Renaissance.
Ambrogio Lorenzetti was active from approximately 1317 to 1348. His earliest dated work is a Madonna and Child from 1319, held in the Museo Diocesano in San Casciano. He died in 1348, believed to have been a victim of the bubonic plague, having made his will on the 9th of August of that year.
The Allegory of Good and Bad Government is located in the Sala dei Nove, also called the Sala della Pace or Room of Peace, inside Siena's Palazzo Pubblico. The frescoes cover three walls with allegorical figures of virtues and two facing panels depicting the effects of good and bad governance on a medieval town and countryside.
The Annunciation of 1344, Lorenzetti's final known work, contains one of the earliest uses of clear linear perspective in Western painting. The diagonals on the floor of the composition create a sense of depth, marking an early step toward the systematic perspective that would define Renaissance art.
The first known visual evidence of the hourglass appears in Lorenzetti's fresco Allegory of Bad Government and Its Effects on Town and Country, painted for the Palazzo Pubblico in Siena. This fresco is part of the larger Allegory of Good and Bad Government cycle completed for the governing council of the Sienese republic.
Ambrogio Lorenzetti is believed to have died of bubonic plague in 1348. He made his will on the 9th of August 1348. His elder brother, the painter Pietro Lorenzetti, is also believed to have died of the plague the same year.