LOST TREASURE OF THE KNIGHTS TEMPLAR 1-3
This series of movies from I guess Denmark or Norway is very good. Four children, two of them turning teens during the series, embark on adventures involving lost treasures such as St Paul's crown, the Holy Grail, the Ark of Covenant, and more. A well filmed, well made kids' series with action, death (but not too much), and great location work. There's also a great deal of interplay between the characters.
Also don't miss CRUADE IN JEANS aka CRUSADE IN TIME or MARCH THROUGH TIME about a boy who goes back in time to the CHILDREN'S CRUSADE