Year 13 BC was either a common year starting on Friday , Saturday or Sunday or a leap year starting on Friday or Saturday ( link will display the full calendar ) of the Julian calendar ( the sources differ , see leap year error for further information ) and a leap year starting on Wednesday of the Proleptic Julian calendar .
Year 13 BC was either a common year starting on Friday , Saturday or Sunday or a leap year starting on Friday or Saturday of the Julian calendar .