The easiest and quickest way to tackle this trophy is presented in the first open area of the game: Minas Ithil. Bear in mind that this should be attempted before starting the last quest of Act I: The Fall. Progress through Act I until you unlock the ability to purify Haedirs (towers with Sauron's Eye). After purifying one you can uncover many hidden things like Artifacts, Shelob's memories or entrance to The Barrows. But most important for this trophy: Ithildin fragment. There are 3 Haedir in the Minas Ithil region. Purify them all, uncover all of the Ithildin and then simply collect them all. Once you have all 6 Ithildin fragments, go to The Barrows, solve the riddle and receive access to a piece of Bright Lord equipment. Congratulations: trophy unlocked!