In mid-18th century, a new Burmese kingdom was the kingdom of Ava which appeared in Alaungpaya and formed the Konbaung Dynasty called the third Burmese Empire in 1700 at the Mandalay. It gradually expanded control over many areas (now is Myanmar), including the conquest of the states in hilly areas of the Shan. Myanmar became a significant powerful country in the region, competed territory and population with the Ayuthaya of Thai kingdom. The competition between the Burmese and Thai became bitter and fierce. 1767, Myanmar was strong enough to send an army to strike down the Thai capital of Ayuthaya. This capital city has been looted and destroyed, ten thousands of Thais arrested and brought into Myanmar to be slavery; Ayuthaya kingdom collapsed.

Qing and Konbaung teritory before Sino Burmese War.

Qing and Konbaung teritory before Sino Burmese War.

Qing Dynasty (China) was anxiety about the growth of Myanmar invaded the country four times in the period from 1766 to 1769 without any success. However, the war with Qing led Myanmar to reduce pressure on Ayutthaya and then lost control of the country. However, the Konbaung dynasty occupied Mrauk U and Tenasserim.

At the end of the 18th century, Myanmar is one of the most powerful countries in mainland Southeast Asia, partly due to the decrease in the Kingdom of Thailand when it was being restored after the decline of the kingdom of Ayuthaya and Vietnam was being under civil war. However, to the early 19th century, history witnessed the development of the Kingdom of Thailand and Vietnam, while Myanmar history witnessed the decline of the Burmese kingdom, the aristocracy class of Myanmar towards the inside rather than towards their partners was Thai and Vietnam and had little trade relations with the outside world. When the British increased their presence in Southeast Asia in the 19th century, the aristocracy class of Burma was less able to assess the threat to them as Thais and they did not have too much ability to cope with.