A 'BC' date will be formatted by removing leading zero's and prepending with a minus sign. Remember, a BC date is always entered as a minus year. For example Mar 1, 7BC is entered as 'Mar 1 -7 => Mar 1 -7 BC'. The actual year calculated is always one year minus due to how BC and year zero are handled. This shows up on the chart pages by following the date, for example 7BC as (-6).