Sunthorn Phu Day is observed in Thailand every June 26 to commemorate the birth of the esteemed royal poet, Phra Sunthorn Vohara, known as Sunthorn Phu. He was born on June 26, 1786, and is celebrated for his literary contributions, particularly his epic poem "Phra Ahai Mani," which he began writing while imprisoned. This observance is officially recognized by the government but is not a public holiday. Sunthorn Phu's legacy includes his appointment as court poet by King Rama II, who appreciated his works, and his subsequent loss of title under King Rama III after he publicly corrected the king's poem. The day serves to honor Phu's significant impact on Thai literature and culture.