The letter “J” was the last letter added to the alphabet and probably wouldn’t have been part of the crusaders’ trap.
In Indiana Jones and the Last Crusade Indy has to retrieve the Holy Grail in order to save his father. Between him and the Grail however are a series of obstacles constructed by knights of the First Crusade. One of these trials is a floor with stones individually marked with various letters of the alphabet. He is “to proceed in the footsteps of the word” and step only on the floor tiles that spell the name of God. The name of God in this case is Jehovah and Indy makes the mistake of stepping on the letter “J” whereby the floor crumbles. He then remembers that in the Latin alphabet, the first letter in the name Jehovah is actually an “I”.
Jehovah’s arrival into the lexicon first appears in the 13th century, but it was originally spelled “Iehouah” with a capital “i”, the letter “J” having not been invented yet. This also means that Jesus’s name wasn’t “Jesus” in his lifetime. In Hebrew he was Yeshua or Yehoshua, or in Aramaic he was Isho or Yeshu. For a long time the letter “J” was just a fancy way of writing the letter “I”. It wasn’t until 1524 that Italian grammarian Gian Giorgio Trissino proposed separating the two letter forms to become two separate letters with two separate sounds.
This raises a typographical problem with the film. The letter “J” didn’t become a part of the alphabet until after 1524 (and in so doing became the last letter added to our alphabet), a few hundred years after the first crusade which was from 1096-1099. So we have to conclude that either:
- the trap wasn’t built for more than 400 years after the first crusade, or …
- every now and then the immortal knight of the Grail updates the trap to include new letter forms over the centuries to keep the trap up to date with the times, or …
- the writers of Indiana Jones and the Last Crusade didn’t do much type research and incredibly audiences were willing to overlook such a flagrant error.