It's a very long and not very adventurous film, but it wasn't boring at all.

It presents Christianity faithfully and from the heart. If you are religious, it is a must see, but it is also a very good historical film. It shows the first contacts between Joseon and the western world. The film and sets are incredibly detailed, grandiose and accurate. We learn about geography, sailing and history while getting one step closer to what actual Christianity is.

We are also shown how Westerners are good and faithful people who spread the gospel, but also how they want to conquer and exploit the unknown.

Kim Tea-Gun was not only Korea's first priest and saint, but he was also the first to receive a Western education and learn European languages. This is huge when you consider how isolated Joseon was for 500 years. Their only contact was with China and Japan.

The actors were very good, although I would expect nothing less from a Korean film. There's a lot of Latin, French and Chinese spoken in it and the story is set in many, many places with surprisingly accurate and large sets.

I can't find the film anywhere, not even on illegal sites. Too bad you can't watch this gem anywhere.
I myself saw it officially distributed in cinemas during the Korean Film Week in Hungary.