Year 40 BC was either a common year starting on Thursday , Friday or Saturday or a leap year starting on Thursday or Friday ( link will display the full calendar ) of the Julian calendar ( the sources differ , see leap year error for further information ) and a common year starting on Friday of the Proleptic Julian calendar .
Year 40 BC was either a common year starting on Thursday , Friday or Saturday or a leap year starting on Thursday or Friday of the Julian calendar .