Wareru (Burmese: ဝါရီရူး, pronounced: [wàɹíjú]; 1253–1307) was the founder of the Ramanya Kingdom located in today's Lower Burma (Myanmar). The kingdom is more commonly known as Kingdom of Hanthawady Pegu (Bago), or simply Pegu although the kingdom's first capital was Martaban (Mottama). By using both diplomatic and military skills, the commoner of Shan and Mon descent successfully carved out a kingdom for the Mon people in Lower Burma following the collapse of the Pagan Empire in 1287. Wareru was nominally a vassal of his father-in-law Ram Khamhaeng of Sukhothai, and of the Mongols, and successfully repulsed attacks by the Three Shan Brothers of Myinsaing in 1287 and 1294.

Wareru was assassinated by his grandsons in January 1307, and succeeded by his brother Hkun Law. The greatest achievements of his reign were his initiative to appoint a commission for the compilation of the Dhammathat, the earliest surviving law code of Burma; and the founding of the Mon kingdom which would prosper for another two and a half centuries.

His Mon name was Magadu (Thai: มะกะโท, rtgs: Makatho, Thai pronunciation: [mä˥.kä˩.tʰoː˧]), and the Shan title is recorded as Wa Row (IPA: /waraʊ/; Thai: วาโร, rtgs: Waro, Thai pronunciation: [wäː˧.roː˧]), from which came the name Wareru.

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