The Horti Leonini, laid out by Diomede Leoni in 1580, is a superb example of the Italian garden. The enormous garden opens into a wide perspective flight, the effect of which is helped by the perfectly geometrical beds of box hedge. Starting at the bottom of the garden, an English wood extends up through to the large square at the top, which was once dominated by the old "torre del cassero", destroyed during the Second World War. In the centre of the lower square, there is a statue of Cosimo III de' Medici, sculpted in 1688 and commissioned by Flavio Chigi in gratitude to the Grand Duke, who had nominated him to be Marquis of San Quirico.

A large part of the antique town walls still stand along with 14 small towers, although some of them are incorporated into other buildings. Unfortunately, nothing remains of the North and South gates, although the partially original Eastern gate is preserved. Probably this was originally preceded by an outer gate, of which only the base remains.
La Collegiata di San Quirico

The present church was built on the site of the old parish church, which dated from the 8 C. La Collegiata three doorways. The first, brought from Siena, is a magnificent example of Romanesque art, constructed of sandstone and travertine. An extraordinary wealth of symbolic religious themes can be seen on the inside of the great round arch. The first "portale di mezzogiorno" (southern door), is obviously still in the Romanesque style, even though there is a hint of the Gothic, is attributed to Giovanni Pisano. With its protruding porch supported on two columns, and with its wonderful balance, it encorporates elements of the Classical, Romanesque and Gothic styles. The bell-tower, as it appears today, was built at the end of the 18 C and replaced the old, arched bell tower. Inside the church, there is a triangular beamed ceiling. The baroque choir was built in 1655, replacing the original apse, and the high altar is in the rococo style. Behind the altar, the magnificent, inlaid panels, by the Siennese Antonio Barili, date from between 1482 and 1502. The nineteen wonderful marquetry panels, of which only seven are still at San Quirico, were acquired by the Marchese Chigi in 1749 and set into the choir. The organ, dating from the 17 C, was revealed after restoration to have a splendid timbre, which is emphasised by the perfect acoustics of the church. In a wing of the transept there is a wonderful polyptych of "Sano di Pietro" (Siennese School - 15 C). This piece was painted expressly for the parish of San Quirico, as can be seen by the red and gold coat-of-arms of the town and the presence of the patron saint.
Palazzo Chigi a San Quirico

Next to the Collegiata and opposite the Palazzo Pretorio (magistrate's palace) - adjoining which, two mediaeval features can be seen - the "porte del morto" (doors of the dead) - rises the huge mass of the Palazzo Chigi. This palace was built in the second half of the 17 C by Cardinal Flavio Chigi, and is now the property of the town council. Unfortunately, due to negligence and harm suffered during the Second World War, the palace remains seriously damaged on its external structure and in its richly frescoed rooms.
Chiesa di San Francesco a San Quirico

The Church of St Francis, which faces the main square, has undergone numerous changes over the centuries. On the high altar there is a very beautiful Madonna attributed to Andrea della Robbia, which perhaps, originally, was part of an Annunciation. On the corbels in the presbytery, there are two wooden polychrome statues of the Angel and the Virgin Mary attributed to Francesco di Valdambrino, a pupil of Jacopo della Quercia.

With its typical Medieval houses, Via Poliziano leads to Porta dei Cappuccini, a massive crenellated tower.

Among the most important monuments are to be mentioned the beautiful Collegiate church of Saints Quirico and Giulitta, built over the ruins of the church of Osenna dating back to the eighth century, with a magnificent Romanesque portal with zoomorphic sculptures and a lintel with the fight between monsters. On the right side there is another Lombardic portal supported by caryatids from the school of Giovanni Pisano.

On the back of the collegiate there is Palazzo Chigi, built by Carlo Fontana for the Cardinal Flavio Chigi. Walking down the via Francigena, today called Via Dante Alighieri, you arrive in Piazza della Liberta’ with the church of San Francesco, bearing a Madonna painted by Della Robbia.
On the square there is the Porta Nuova, opening to the Horti Leonini, an Italian style garden built by Diomede Leoni in 1540.
Continuing you come to the church of Santa Maria Assunta, in Romanesque style with Lombardic influences, with another interesting portal built with material coming from the Abbey of Sant’Antimo.

Of the defensive structures there are remains of most of the 15th century walls, with just some portions missing. 14 towers and turrets are still visible, some of which are incorporated in other buildings. The Porta Nuova gate is still there, amended several times over the centuries and the original Porta dei Cappucini gate with a central six-sided shelves crowned by small stones that support the arch. Finally in the Horti Leonini garden there are the remains of the city gate tower that was partially destroyed during the German retreat in 1944.