If "you" is singular and the subject is masculine or feminine:
* "You had seen" (perfect active indicative): *Vidisti*
If "you" is singular and the subject is neuter:
* "You had seen" (perfect active indicative): *Vidisti*
If "you" is plural:
* "You had seen" (perfect active indicative): *Vidistis*
If you want to emphasize the completion of the action:
* "You had seen" (perfect active indicative): *Vidĕrās*
If you need the passive form:
* "You had been seen" (perfect passive indicative): *Visus erās* (singular) or *Visi erātis* (plural)
Important Note: Latin grammar has different verb tenses and moods, so the translation of "You had seen" can vary depending on the specific context.