Somdet Phra Boromma Trailokanat Songtham (full Thai title: สมเด็จพระเจ้าทรงธรรม; RTGS: Somdet Phra Chao Songtham) was the King of Ayutthaya from 1611 to 1628 of the House of Sukhōday. His reign was marked as prosperity after the First Fall of Ayutthaya and saw the commencement of trade with foreign nations especially the Dutch and the Japanese. Songtham filled his guards with foreign mercenaries most notably the Japanese – Yamada Nagamasa.