Is it obligatory to repeat prayers that were performed in a mosque containing graves, given the uncertainty regarding the chronological order of the mosque's and the graves' construction, or the location of the graves relative to the Qibla?

If the graves are within the mosque’s courtyard, enclosed by its fence, then they are considered part of the mosque, and it is not permissible for a grave to remain inside the mosque’s courtyard. Rather, it must be removed from it. If the grave was there first, it must be cleared and removed from the mosque by having the mosque’s fence encompass an area outside of it. If the mosque was built first, then the grave should be exhumed and reburied in the common cemeteries. However, if the courtyard is not enclosed by the mosque’s fence, it is not considered part of the mosque, and therefore there is no issue with the validity of the prayer. Ignorance of the presence of a grave absolves one of sin and does not necessitate repeating the prayers. The default assumption is the absence of doubtful graves.