After the Grail was entrusted to Joseph of Arimathea, it disappeared, and was lost for a thousand years before it was found again by three knights of the First Crusade. Three brothers, to be exact.
13 seconds sound clip from the Indiana Jones and the Last Crusade movie soundboard.
You can hear this line at 00:20:14 in the Blu-ray version of the movie.
Quote context
[...]
- The Holy Grail's final resting place described in detail.
- Just the same, an attempt to recover the Grail is currently underway.
- Let me tell you another bedtime story, Dr. Jones.
- I've heard this one, as well.
- This is the manuscript in which the friar chronicled the knight's story.
[...]