Peace negotiations proved unsuccessful and the fighting in Saigon continued. Ultimately in 1861, the French brought additional forces to bear in the Saigon campaign, advanced out of the city and began to capture cities in the Mekong Delta. On 5 June 1862, the Vietnamese conceded and signed the Treaty of Saigon whereby they agreed to legalize the free practice of the Catholic religion; to open trade in the Mekong Delta and at three ports at the mouth of the Red River in northern Vietnam; to cede the provinces of Biên Hòa, Gia Định and Định Tường along with the islands of Poulo Condore to France; and to pay reparations equivalent to one million dollars.