Gwanggaeto Stele
The earliest Korean reference to Japanese "Wa" ("Wae" in Korean) is the 414 CE Gwanggaeto Stele that was erected to honor King Gwanggaeto the Great of Goguryeo (r. 391–413 CE). This memorial stele, which has the oldest usage of "Wakō" (倭寇, "Japanese pirates", "Waegu" in Korean), records Wa as a military ally of Baekje in their battles with Goguryeo and Silla. Some scholars interpret these references to mean not only "Japanese" but also "Gaya peoples" in the southern Korean Peninsula. For instance, Lee suggests,