Bayan ya ci daular Hariphunchai, Sarki Mangrai ya kafa Wiang Kum Kam a matsayin sabon babban birninsa a shekara ta 1294, dake gabashin kogin Ping.Sai dai saboda yawaitar ambaliya, ya yanke shawarar matsar da babban birnin kasar.Ya zaɓi wani wuri kusa da Doi Suthep, inda wani tsohon garin mutanen Lua ya taɓa tsayawa.A shekara ta 1296, an fara gini a Chiang Mai, ma'ana "Sabon Birni", wanda ya kasance babban babban birni a yankin arewa tun daga lokacin.Sarki Mangrai ya kafa Chiang Mai a shekara ta 1296, inda ya mai da ita cibiyar tsakiyar masarautar Lan Na.A karkashin mulkinsa, yankin Lan Na ya faɗaɗa ya haɗa da yankunan arewacin Thailand a yau, tare da wasu kaɗan.Har ila yau, mulkinsa ya ga tasiri a yankuna a Arewacin Vietnam , Arewacin Laos , da yankin Sipsongbanna a Yunnan, wanda shine mahaifar mahaifiyarsa.Duk da haka, zaman lafiya ya katse lokacin da sarki Boek na Lampang, dan Sarkin Yi Ba, ya kaddamar da hari a Chiang Mai.A cikin wani gagarumin yaƙi, ɗan Mangrai, Yarima Khram, ya fuskanci sarki Boek a cikin giwa a kusa da Lamphun.Yarima Khram ya samu nasara, wanda ya tilastawa sarki Boek ja da baya.Daga baya an kama Boek a lokacin da yake kokarin tserewa ta tsaunin Doi Khun Tan kuma aka kashe shi.Bayan wannan nasara, sojojin Mangrai sun karbe iko da Lampang, inda suka tura sarki Yi Ba ya sake komawa kudu zuwa Phitsanulok.