Siam found herself between GB and France in Chulalongkorn reign. Siam was too small to resist the French pressure.
On July 15 1867 Siam signed a treaty with France, those are:
1. Siam recognized the French protectorate over Cambodia
2. The treaty between Siam and Cambodia was declared null.
3. Siam would not demand taxes and tribute from Cambodian.
4. Battambong and Siemrap belonged to Siam
5. The Thais and Cambodians could trade with one another.
6. French ships had a right to navigate in Mekong River.
7. French would force Cambodia to abide by this treaty.
8. The treaty was made in French and Thai version.
9. The treaty was to be ratified at Bangkok within 5 months.
In 1886, Siam lost some territory to French, Laos and British Burma accorded the foreign powers intercede.
After that King Chulalongkorn declared Thailand as an independent kingdom on the 23rd of October, making this day as a national holiday. Every year this national holiday is celebrated in commemoration of this event and people lay wreaths in memory of king they called "Phra Piya Maharaj"