Saw O was the third king of Hanthawaddy Pegu

Hanthawaddy Kingdom

The Hanthawaddy Kingdom was the dominant kingdom that ruled lower Burma from 1287 to 1539. The Mon-speaking kingdom was founded as Ramannadesa by King Wareru following the collapse of the Pagan Empire in 1287 as a nominal vassal state of Sukhothai Kingdom, and of the Mongol Yuan dynasty...

, who reigned from 1311 to 1323. Saw O succeeded his maternal uncle Hkun Law

Hkun Law

Hkun Law was the second king of Hanthawaddy from 1307 to 1311. He ascended to the throne after his elder brother King Wareru was assassinated. Hkun Law was of Shan and Mon descent....

, who was assassinated by Saw O's father Min Bala in 1311. When Saw O ascended to the throne, his kingdom was a nominal vassal

Vassal

A vassal or feudatory is a person who has entered into a mutual obligation to a lord or monarch in the context of the feudal system in medieval Europe. The obligations often included military support and mutual protection, in exchange for certain privileges, usually including the grant of land held...

 of Sukhothai

Sukhothai kingdom

The Sukhothai Kingdom ) was an early kingdom in the area around the city Sukhothai, in north central Thailand. The Kingdom existed from 1238 till 1438...

. He was even married to a daughter of the king of Sukhothai. But as the power of Sukhothai declined, Saw O took possession of the Tenasserim coast from his nominal overlord Sukhothai.

His reign was largely peaceful and prosperous, and the kingdom's northern frontier was quiet. (Unlike Lower Burma under a single kingdom, Upper Burma remained disunited, split among petty kingdoms. None of the Upper Burmese kingdoms was in a position to make war with a unified south.) However the king's desire to be independent of Sukhothai led to future wars between the two kingdoms.

Saw O died in October 1324, and was succeeded by his brother Saw Zein

Saw Zein

Saw Zein was the fourth king of Hanthawaddy Pegu from 1324 to 1331. A nephew of the kingdom's founder King Wareru, Saw Zein succeeded his brother King Saw O in 1324. He lost the southern territories of Tenasserim coast back to his nominal overlord Sukhothai, and looked to expand his territory...

.

Background

Like his predecessors, Saw O was also of Shan and Mon

Mon people

The Mon are an ethnic group from Burma , living mostly in Mon State, Bago Division, the Irrawaddy Delta, and along the southern Thai–Burmese border. One of the earliest peoples to reside in Southeast Asia, the Mon were responsible for the spread of Theravada Buddhism in Burma and Thailand...

 descent. (He was at least a quarter Shan as his mother Hnin U Yaing

Hnin U Yaing

Hnin U Yaing was a princess of Hanthawaddy Kingdom who was the sister of two kings, Wareru and Hkun Law, and the mother of two kings Saw O and Saw Zein. She was also a paternal great-grandmother of Razadarit, considered the greatest Hanthawaddy king...

, sister of King Wareru

Wareru

Wareru was the founder of the Ramanya Kingdom located in today's Lower Burma . The kingdom is more commonly known as Kingdom of Hanthawady Pegu , or simply Pegu although the kingdom's first capital was Martaban...

, was half-Shan. Part of his name Saw was the Shan honorific Sao.)

He had a son Saw E

Saw E

Saw E or Saw E Kankaung was the sixth king of Hanthawaddy Pegu, who ruled for a few months in 1331. He was a son of King Saw O and Princess May Hnin Htapi of Sukhothai. After the death of his uncle King Saw Zein in 1331, the young price was placed on the throne by Queen Sanda Min Hla...

(future king) and a daughter with Princess of Sukhothai.