Currently Alternative Dates sort alphabetically - not very useful in a lot of cases. To solve this issue, when a user clicks on "alternative calendar" in addition to the freetext date and time field relabeled as "display value" a gregorian calendar field is displayed next to it. That way a user can input whatever they want in the date and time field (now called the display value field) e.g. NBT 5,080.33.26 and beside it enter 07/30/4900 B.C 3:10 AM in the Gregorian Calendar field. All alternative dates are sorted in gregorian calendar order but are displayed on timelines as the alternative calendar "display value".