Siege of Tourane The Siege of Tourane ( September 1858 – March 1860 ) was a Vietnamese victory during the Cochinchina Campaign , a punitive campaign against the Vietnamese launched by France and Spain in 1858 . A joint Franco - Spanish expedition under the command of Admiral Charles Rigault de Genouilly captured Tourane ( modern Da Nang ) in September 1858 , but was then besieged in the city by the Vietnamese and forced eventually to evacuate it in March 1860 . Background . In 1857 the Vietnamese emperor Tự Đức executed two Spanish Catholic missionaries . This was neither the first nor the last such incident , and on previous occasions the French government had overlooked such provocations . On this occasion Tự Đức ' s timing was terrible . France and Britain had just despatched a joint military expedition to the Far East to chastise China , and the French had troops to hand with which to intervene in Vietnam . In November 1857 the French emperor Napoleon III authorised Admiral Charles Rigault de Genouilly to launch a punitive expedition to teach the Vietnamese a long - overdue lesson . In the following September , a joint French and Spanish expedition landed at Tourane , whose fine , sheltered harbour would make it a good base of operations for a campaign against Annam . Forces engaged . Rigault de Genouilly ' s flagship was the screw - powered 50 - gun frigate " Némésis " . He was accompanied by the screw - powered 12 - gun corvettes " Primauguet " and " Phlégéton " , the steam - gunboats " Alarme " , " Avalanche " , " Dragonne " , " Fusée " and " Mitraille " , and the steam transports " Durance " , " Saône " , " Gironde " , " Dordogne " and " Meurthe " . The Spanish navy was represented by the armed despatch vessel " El Caño " . The transports carried a landing force of two overstrength battalions of French marine infantry ( 1 , 000 men ) , a marine artillery battery and 1 , 000 troops drawn from the Spanish garrison of the Philippines ( 550 Spanish troops and 450 Filipino light infantry , mostly Tagalogs and Visayans , known to the French as " chasseurs Tagals " ) . Tourane lay on the southern shore of the Bay of Tourane . Its main defences were sited on the Tien Cha peninsula , on the eastern side of the bay . The Vietnamese had built five major forts along the sheltered western side of the peninsula , covering the approaches to the town ( see map ) . These forts were known respectively to the French as Fort de l ' Aiguade , Fort de l ' Observatoire ( Observatory Fort ) , Fort du Nord ( Northern Fort ) , Fort de l ' Est ( Eastern Fort ) and Fort de l ' Ouest ( Western Fort ) . Several shore batteries were deployed between these forts . These were potentially formidable defences : The bay was defended by several forts . Some of these dated from the period of Pigneau de Béhaine and Olivier de Puymanel , but they were all in good condition , ' very superior ' , said the admiral , after visiting them , ' to anything we saw in China ' . The cannons , of large and medium calibre , were mounted upon modern gun - carriages , the powder came from Britain , and the infantry was armed with good rifles , made in Belgium or France . Their arms , in the hands of trained soldiers , would be capable of sinking the entire naval division , and we were expecting the defenders at the very least to put up a serious resistance to it . Tourane was defended by a Vietnamese garrison of 2 , 000 men under the command of the mandarin Le Dinh Ly . Capture of Tourane and the Tien Sa peninsula . The allied expedition arrived off the entrance to Tourane Bay at nightfall on 31 August . At dawn on 1 September the warships took up positions facing the five Vietnamese forts on the Tien Sa peninsula . During the morning of 1 September Admiral Rigault de Genouilly summoned the Vietnamese to hand over the forts within two hours . The summons was taken ashore by a French staff officer and laid at the entrance to the Fort de l ' Aiguade . No response was received within the stipulated period , and the French admiral ordered the allied flotilla to open fire , hoisting a French flag at the main mast of " Némésis " and a Spanish flag at the mizzen mast . The warships of the allied flotilla soon dismounted the guns in the northern group of Vietnamese forts . The Vietnamese response was feeble , and none of the allied ships suffered any damage . Rigault de Genouilly then put ashore the landing companies of " Némésis " , " Primauguet " and " Phlégéton " , under the orders of " capitaine de vaisseau " Reynaud . The sailors captured their first objective , the Fort de l ' Aiguade , with little trouble , charging into the Vietnamese positions with cries of ' Vive l ' Empereur ! ' Rigault de Genouilly ' s summons was found on a table inside the fort , unopened . The attackers also overran a Vietnamese shore battery a little to the west of the fort . While this attack was being made , French soldiers went ashore in their turn . The southern objectives , Eastern Fort and Western Fort , were also taken without difficulty . Two French gunboats and the Spanish despatch vessel " El Caño " anchored off the entrance to the Da Nang river and bombarded Western Fort and Eastern Fort . A shell burst inside Eastern Fort as the attackers approached and the survivors of the Vietnamese garrison abandoned their positions forthwith , as did the defenders of Western Fort . Most of the Vietnamese made their escape from the Tien Sa peninsula , but the defenders of Observatory Fort were unable to evacuate their positions in time . The French stormed the fort , and its defenders were either killed where they stood or taken prisoner . The allies followed up their victory by occupying Tourane and the Tien Sa peninsula . Admiral Rigault de Genouilly left Da Nang with the bulk of his forces on 2 February 1859 , to launch an attack on Saigon . The French left only a small garrison of soldiers and sailors at Tourane , under the command of " capitaine de vaisseau " Thoyon , and two gunboats . Meanwhile , the Tourane peninsula had been placed under siege by a Vietnamese army under the command of Nguyen Tri Phuong . The siege lasted for several months , though there was relatively little fighting . The Vietnamese adopted a scorched earth policy , laying waste the countryside around Tourane in the hope of starving the French and Spanish out . In April 1859 , in the wake of his capture of Saigon on 17 February , Rigault de Genouilly returned to Tourane with the bulk of his forces to reinforce Thoyon ' s hard - pressed garrison . The French made two attacks on the Vietnamese positions later in the year . On 8 May Rigault de Genouilly personally led 1 , 500 French soldiers and sailors in a successful assault on the Vietnamese trenches . A number of Vietnamese earthworks were destroyed and several cannon were captured and brought back to the French lines . French casualties were 78 men killed and wounded . Engagement at Cam Le , 15 September 1859 . A second , equally successful , assault was made on 15 September on the Vietnamese positions at Cam Le . The Vietnamese had fortified a defence line one and a half kilometres long , consisting of strongpoints linked by trenches . Ditches filled with water had been dug in front of the trenches , and the defences were crowned with bamboo stakes filed to sharp points . The allied garrison of Tourane had recently been reinforced by eight companies of marine infantry , and Rigault de Genouilly was able muster three columns for the attack , under the respective commands of Lieutenant - Colonel Reybaud , Colonel Lanzarote and " capitaine de vaisseau " Reynaud , backed by a strong reserve under the command of " chef de bataillon " Breschin . The French and Spanish stormed the Vietnamese lines and put their defenders to flight . French casualties at Cam Le were 10 men killed and 40 wounded . Several hundred Vietnamese were killed and wounded , and the French and Spanish also captured 40 enemy cannon . The Vietnamese commander Le Dinh Lai was mortally wounded in the engagement . Despite these impressive tactical victories , the French were unable to break the siege of Tourane . Meanwhile , disease was taking a heavy toll of the allied expedition . Cholera broke out both among the allied landing force and on the warships . Between 1 June and 20 June 1859 , 200 French troops died from cholera in Tourane , and one battalion that joined the garrison at the end of April 1859 lost a third of its strength in two months . Capture of the Kien Chan forts , 18 November 1859 . In the autumn of 1859 Rigault de Genouilly , whose conduct of the war had come under criticism , was repatriated to France and replaced in command of the allied expedition by Rear Admiral François Page . Page disembarked in Tourane on 19 October , and immediately after his arrival offered peace terms to the Vietnamese : an end to the persecution of Christians , the installation of French consuls in Vietnam and certain commercial privileges . These were relatively moderate terms , but the Vietnamese did not accept them . Instead , they spun out the negotiations , believing that the French would eventually leave Vietnam empty - handed . Page thereupon ordered a third attack on the Vietnamese siege lines at Tourane . The attack was directed against the Kien Chan forts , to the north of Tourane Bay , which barred the route to Huế . Its chief purpose was political rather than military , namely to impress upon the Vietnamese that the French were not prepared to make peace at any price . On 18 November 1859 " Némésis " and " Phlégéton " ( towed respectively by " Prégent " and " Norzagaray " , a despatch vessel recently bought at Manila ) , the gunboats " Avalanche " and " Alarme " , the transport " Marne " and the Spanish despatch vessel " Jorgo Juan " ( which had replaced " El Caño " ) anchored off the Kien Chan forts and opened a devastating bombardment . Before long the allied warships had wrecked the forts and dismounted their cannon . The casualties were not all on the Vietnamese side , however . Lieutenant - Colonel Dupré - Déroulède , the senior French engineering officer , was cut in two by a cannonball while standing on the bridge of " Némésis " . The same shot killed a French sailor , wounded several others , and spattered Admiral Page with blood . Once the forts were silenced a French landing force was put ashore and found that the Vietnamese had abandoned their positions . Once again the French had won a fine tactical victory , overwhelming the Vietnamese defenders and capturing the forts , but once again the victory had no strategic significance . Allied evacuation of Tourane , 22 March 1860 . Eventually the French decided to evacuate Tourane and concentrate their efforts around Saigon . Preparations for a methodical evacuation began in February 1860 . The French and Spanish disarmed and blew up one by one the Vietnamese forts they had occupied and burned their barrack huts . The last soldiers of the landing force re - embarked on 22 March 1860 , without hindrance from the Vietnamese . The only trace left behind of the twenty - month Franco - Spanish occupation of the Tourane peninsula was a cemetery in which the allied dead had been buried . Aftermath . The Tourane expedition had tied down French resources unprofitably and drained French manpower , and the eventual evacuation of Tourane was an embarrassing confession of failure . Tự Đức was immensely encouraged by the outcome of the siege , and had the news of the allied evacuation proclaimed throughout Vietnam . In the long run , however , the failure of the expedition made no difference to the course of the war . The military stalemate around Saigon was broken in 1861 , when the ending of the war with China freed French military resources for action in Vietnam , by an important French and Spanish victory at Ky Hoa . The allies now began to gain the upper hand . In April 1861 , Mỹ Tho was captured . In early 1862 the French captured Bien Hoa and Vĩnh Long . These victories forced the Vietnamese to sue for peace in April 1862 . By then the French were not in a merciful mood . What had begun as a minor punitive expedition had turned into a long , bitter and costly war . It was unthinkable that France should emerge from this struggle empty - handed , and Tự Đức was forced to cede the three southernmost provinces of Vietnam ( Biên Hòa , Gia Định and Định Tường ) to France . Thus , casually , was born the French colony of Cochinchina , with its capital at Saigon .