The Hanthawaddy Kingdom (Burmese: ဟံသာဝတီ ပဲခူး နေပြည်တော်; Mon: ဟံသာဝတဳ, [hɔŋsawətɔe]; also Hanthawaddy Pegu or simply Pegu) was the dominant kingdom that ruled lower Burma (Myanmar) from 1287 to 1539 and from 1550 to 1552. The Mon-speaking kingdom was founded as Ramaññadesa ((Burmese: ရာမညဒေသ, Mon: ရးမည) by King Wareru following the collapse of the Pagan Kingdom in 1287 as a nominal vassal state of the Sukhothai Kingdom and of the Mongol Yuan dynasty. The kingdom became formally independent of Sukhothai in 1330 but remained a loose federation of three major regional power centres: the Irrawaddy Delta, Bago, and Mottama. Its kings had little or no authority over the vassals. Mottama was in open rebellion from 1363 to 1388.