Battle of Marciano The Battle of Marciano ( also known as the Battle of Scannagallo ) occurred in the countryside of Marciano della Chiana , near Arezzo , Tuscany , on August 2 , 1554 , during the Italian War of 1551 . The battle marked the defeat of the Republic of Siena in its war against the Duchy of Florence , and resulted in Siena losing its independence and being absorbed into the Grand Duchy of Tuscany . Prelude . In 1554 , Cosimo I de ' Medici , with the support of Emperor Charles V , launched a grand campaign to conquer Florence ' s last remaining rival in Tuscany , the Republic of Siena . His army was under the command of Gian Giacomo Medici , Marquess of Marignano , best known as " Medeghino " ( " Small Medici " ) . The Florentine - Imperial troops were divided into three corps : Federico Barbolani di Montauto , with 800 men , landed in southern Tuscany to conquer the area of Grosseto ; Rodolfo Baglioni , with 3 , 000 men , invaded the Val di Chiana to conquer Chiusi , Pienza and Montalcino ; and the main corps under Medeghino himself , consisting of 4 , 500 infantry , 20 cannons , and 1 , 200 sappers , was deployed at Poggibonsi for the main attack against Siena . The Senese entrusted the defence to Piero Strozzi , a fierce rival of the Medici family and a general in French service . French troops , as well as some Florentine exiled by the Medici , took part to the war under the Sienese aegis . The Florentine troops approached Siena in the night of January 26 , 1554 . After an initial failed assault , the Marquess of Marignano laid siege to the city , although his men were not numerous enough to totally cut it off from the countryside . Both Baglioni and Montauto failed to capture Pienza and Grosseto . French ships harassed the Florentine resupply lines at Piombino . Cosimo replied to the initial setbacks by hiring Ascanio della Cornia with 6 , 000 infantry and 300 cavalry , and waiting for further Imperial reinforcements . On June 11 , Strozzi attempted a sally to relieve the pressure on Siena , leaving some French units in the city . He moved towards Pontedera , forcing Medeghino to raise the siege to follow him . This did not prevent Strozzi from joining with a French contingent with 3 , 500 infantry , 700 horse and 4 cannons in the territory of Lucca . On June 21 , Strozzi conquered Montecatini , but did not feel confident enough to join in a pitched battle against Medeghino , waiting instead for further French reinforcements which were to arrive at Viareggio . He had , in total , 9 , 500 infantry and perhaps 1 , 200 cavalry , while Medici had 2 , 000 Spanish , 3 , 000 German , and 6 , 000 Italian infantry , as well as 600 cavalry , not to mention further troops from Spain and Corsica which had recently landed at Bocca d ' Arno . His brother , Leone Strozzi , had been killed by an arquebus ball in the course of the struggle for Grosseto . Strozzi therefore marched back to Siena , where the supply situation had become desperate . In July , he failed to capture Piombino , in southern Tuscany , the only port from which the French supplies could reach Siena . On July 17 , conscious that only a victory in a pitched battle could save the city , he tried a third sally in the Val di Chiana , in direction of Arezzo , leaving 1 , 000 infantry and 200 cavalry as a garrison under Blaise de Montluc . His field army included 14 , 000 infantry , about 1 , 000 cavalry , and five guns . His force easily overwhelmed the small Florentine garrisons on his way , although the attempt , on July 20 , to conquer Arezzo failed . He managed to capture Lucignano , Marciano della Chiana , Foiano and other centres in the following days . After some days of inactivity , Medeghino raised the siege of Siena and moved to meet Strozzi . Battle . After some initial skirmishes , the two large armies clashed when Strozzi , short of food , decided to retire towards Lucignano in the night of August 1 . In the morning of the following day , it was clear that his manoeuver had not been successful , and he was forced to lay battle against the Florentine - Imperial troops that were stalking and harassing his moving troops . The Senese had : c . 1 , 000 French - Senese horse on the right wing ; then followed , on the centre , 3 , 000 Landsknechts , with 3 , 000 Grisons infantry behind them and other 3 , 000 French infantry on their left ; the left wing was formed by 5 , 000 Italian infantry under Paolo Orsini . Strozzi ' s army occupied the slight slope of a hill that descended towards the Scannagallo creek . Il Medeghino deployed 1 , 200 light cavalry on his left wing , backed by 300 " Uomini - d ' Arme " ( heavy cavalry ) under Marcantonio Colonna . The centre infantry corps was composed by 2 , 000 Spanish veterans and other Corsican recruits and 4 , 000 German Landsknecht s under Niccolò Madruzzo . The right wing was formed by 4 , 000 Tuscan , 2 , 000 Spanish and 3 , 000 Roman poorly trained infantry , in three rows , with the few artillery available behind . The reserve included 200 Spanish soldiers , veterans of the Ottoman – Habsburg wars , and a company of horse arquebusiers from Naples . The battle began with the attack of the Medeghino ' s cavalry wing , whose impetus easily routed its French - Senese counterpart , which fled towards Foiano . It has been reported that the French commanders of that unit , Valleron and Fourquevaux , had been bribed by the Medeghino with 12 tin flasks filled with golden coins . To counter this first setback , Strozzi decided to launch down from the hill the German infantry of his center . A chaotic melee ensued , but soon the momentum of the Senese attack began to wane under the fire of the Imperial artillery , which also disorganized the Swiss attempting to relieve the first line . When Il Medeghino ordered also to his men to launch themselves against the enemy , the German and Swiss began to panic . This turned into a complete route when Colonna ' s heavy cavalry , who had pursued for a while the French - Senese cavalry , attacked from behind the Germans fighting across the Scannagallo . The French infantry on the right wing maintained its battle order , and , surrounded on every side , defended desperately until the end . Strozzi himself was wounded three times and was carried away by his guards . His lieutenant Clemente della Cervara died shortly afterwards the battle for the wounds received . The battle lasted for only two hours , from 11 AM to 1 PM . The Senese army suffered 4 , 000 dead , 4 , 000 wounded or prisoners . Strozzi escaped the capture . Aftermath . Il Medeghino easily subdued the neighbouring castles in the days following the battle , and was subsequently able to lay a tighter siege to Siena . Cruel measures were adopted to prevent the peasants taking supplies into the city . In March 1555 he destroyed a corps of 1 , 300 mercenaries trying to escape to collect food . Unable to receive substantial supplies and reinforces from the French , the city surrendered on April 17 , 1555 while the remaining Senese forces withdrew to Montalcino . The Republic of Siena finally disappeared in 1559 and was thenceforth incorporated into the Grand Duchy of Tuscany . The Grand Duke ordered that a large fortress be constructed as a precaution against the risk of further rebellion by the Sienese , and this has presided over the city , from its south - eastern ( Florentine ) side , since its completion in 1563 .