For high-quality, legal streaming, the following platforms have hosted the series:
For the best video quality and accurate translations, official platforms are recommended: Dae Jo Yeong (TV Series 2006–2007) - IMDb dae jo yeong english subtitles download telegram
What I can offer instead is:
Searching for English subtitles for the historical K-drama Dae Jo-yeong dae jo yeong english subtitles download telegram