The Book of Occultation — al-Ṭūsī · Hadith 768 (#Ḥadīth #17)
Chapter 52 | Some Qualities, practices and manners of the Master of the Age
499- وفي خبر آخر (أنه) يفتح قسطنطينة والرومية وبلاد الصين.
H 499 - In another report, he would conquer Constantine, Rome and China.
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).