Sanpet III (Thai: สรรเพชญ์ที่ 3) or Ekathotsarot (Thai: เอกาทศรถ;-1620) was the King of Ayutthaya from 1605 to 1620 succeeding his brother Naresuan. His reign was mostly peaceful as Siam was then a powerful state through the conquests of Naresuan. Also during his reign that foreigners of various origin began to fill the mercenary corps. In particular, the king had a regiment of professional Japanese guards under the command of Yamada Nagamasa.[1]:51
During Ekathotsarot's reign, the English first came to Siam in 1612.[1]:53[2]:242