Ambrogio Lorenzetti (1290 – 1348) was an Italian painter of the Sienese school. He was active between approximately from 1317 to 1348. Although having done work in Florence, Ambrogio Lorenzetti was known within the Sienese School of painters. This school of painting from Siena, Italy, was an elegant style that was said to rival, at time, even the Florentine painters throughout the 13th and 15th centuries.
Lorenzetti’s work survives in history with a painting from 1328 that contains the first documented existence of the hourglass. Very few of Lorenzetti’s pieces have survived and his earliest known work was the, Madonna and Child, painted in 1319. His other works, additional to the wall frescos on the Sala dei Nove, include a fresco at San Francesco titled The Investiture of St. Louis of Toulouse (1329), an altarpiece in San Procolo from 1332 titled, Madonna and Child with Saints Nicholas and Proculus, another fresco at San Francesco titled Franciscan Martyrdom at Bombay (1336), and an altarpiece of Santa Petronilla commissioned for the altar of San Crescenzo in Siena Cathedral from 1342.
Though he also contributed a piece of historic relevance called, Well-Governed Town and Country, which is a pictorial encyclopedia that depicts an idealistic countryside, or medieval “borgo.” This piece was a familiar style of Lorenzetti’s from frescos he created on the walls of Sala dei Nove (the Hall of the Nine), or the Sala della Pace (Hall of Peace) in Siena’s Palazzo Pubblico. They are important works in Siena’s preservation of history, and exhibit the artist as an astute political and moral observer.
These frescos, painted from 1337 – 1339, were secular representations of allegorical figures of virtue in how a republic was governed. Aside from, Well-Governed Town and Country, there are three more, less preserved frescos, Allegory of Good Government, Effects of Good Government, and Allegory of Bad Government and its effects on Town and Country. They are complex, panoramic works that contained the Gothic influence of other Sienese painters like Simone Martini (1284 – 1344).

The Allegory of Good Government carries a strong social message of the value of the stable republican government of Siena. It combines elements of secular life with references to the importance of religion in the city at the time. While classified as medieval or proto (pre)-renaissance art, these paintings show a transition in thought and an evolution in theme from earlier religious art.

Ambrogio Lorenzetti died from a plague in 1348.

Ambrogio Lorenzetti was certainly the most inventive Sienese artist of the early 14th century. Many of his innovations in naturalism are without parallel; many of his works are characterized by iconography that is equally original.
The peaceful and gently lyrical temperament of Ambrogio Lorenzetti is in complete contrast to bis brother's fiery and often intensely dramatic spirit. Vasari did not realize that the two were related, and wrote of Ambrogio that bis manners "were. .. more those of a gentleman and philosopher than those of an artist," and he speaks about his love of literature and bis intellectual acumen, qualities that enabled him to turn bis hand both to sacred painting and to historical, allegorical and other "profane" themes, to pick up hints from classical antiquity and from the fabled Orient, to be a cosmographer and cartographer, and above all to bring profundity and boldness of ideas to bis work, and to revolutionize accepted notions of iconography.[1]

Unlike Pietro Lorenzetti, Ambrogio shows no signs of the influence of Duccio in his painting. He is known to have been in Florence earlier than 1321, and his earliest known painting was found in Florentine territory: dated 1319, it comes from the church of Sant'Angelo at Vico l'Abate, and is now in the Musea di Cestello in Florence. However, the spirit of Giotto visible even in this work does not tend, as in Pietro, to create three-dimensionality by means of strong contrasts of colour and of light and shade, but rather to define the structure of the forms by a precise vigour of outline, and with strong lines surrounding clear and vivid chromatic planes. Even his experiments in perspective, which Ambrogio pursued instinctively and in which he attained some fascinating results, are to be seen in this tension between line and colour.
In 1324 the artist was in Siena, where he must have done a lot of work, as we see from numerous pictures including - presumably in this period - a Madonna at Brera and the famous Madonna del Latte, formerly in the monastery of Lecceto and now in the Archbishop's Palace in Siena. The calm, gentle and interconnected development of the linear structures here bind the image of the Child to that of the Mother in an admirable and moving unity of composition. But in 1327 he is recorded as being a member of the "Arte dei Medici e Speziali" in Florence, the guild to which painters and pigment merchants also belonged. Two important altarpieces used to be in the Florentine church of San Procolo, a triptych which seems once to have borne the signature and the date of 1332, now vanished, and which was reconstructed at the Uffizi in1959, and an altar-frontal, which like Martini's altarpiece of the Blessed Agostino Novella, appears to have had in the centre an image of St. Nicholas of Bari, now either lost or unidentified, flanked by four panels depicting miracles performed by the Saint, now preserved in the Uffizi. In these panels the artist may have given one of the earliest proofs of his skill at architecture and landscape, qualities that foreshadow the frescoes of the Good and Bad Government: the great frescoes in the Palazzo Pubblico in Siena which allegorically sum up so much of the ideals of 14th-century Tuscany, and incidentally give us a most wonderful and exact picture of the daily life and customs of the time.

Ambrogio Lorenzetti's most revolutionary achievement - one of the most remarkable accomplishments of the Renaissance - is the fresco series that lines three walls of the room in the Palazzo Pubblico where Siena's chief magistrates, the Nine, held their meetings (Sala dei Nove). These frescoes are collectively known as Allegory and Effects of Good and Bad Government. The aim of the painting is to exalt the political creed of the government of the Nove, who were Guelphs and retained power in Siena until 1355. It elaborates on two themes already foreshadowed in the inscriptions on the Maestà of Simone Martini: that of Justice on the one hand, and on the other the subordination of private interests to those of the common good, according to a concept of Aristotelian origin that was expressed in the work of St. Thomas Aquinas and popularized in the early 14th century by the Dominican friar Remigio de' Girolami. The painting works essentially on two levels, one allegorical and symbolic and other concerned with description and exemplification, while whole cycle covers three walls of the great hall. On the wall opposite the window, 7.7 metres long, is Allegory of Good Government. This is
personified by the Commune, represented by a venerabie old dressed in the colours of the Balzana, the black and white Sienese coat-of-arms, seated on a throne and surrounded by the four Cardinal Virtues and by Magnanimity and Peace. Homage is being paid to these figures by twenty-four citizens (in memory of the government of the Twenty-Four, which between 1236 and 1270 marked the entry of the common people into the government of the Commune, though they are also symbolic representations of the various civic officers and magistrates), and these are linked by two woven cords ("concordes") which Conrord gathers up from under the scales of Justice at the instigation of Wisdom. Above Good Government are the three Theological Virtues, and at bis feet is the she-wolf with the twins Romulus and Remus, an allusion to the Roman origins of Siena. On the right are fully-armoured knights and foot-soldiers symbolizing the

Flanking the Allegory are two other paintings on perpendicular walls: Effects of Good Government and Effects of Bad Government. Both these frescoes depict a recognizable view of Siena and its countryside.

In the allegorical representation of Good Government, the prosperous townspeople are trading and dancing in the streets. Beyond the city walls is a lush countryside in which crops are harvested.

In the allegory of Bad Government, crime is rampant and diseased citizens roam a crumbling city. The countryside suffers from drought.