Return to ‘default’ order

I have a table with a date column but instead of having actual dates, it has a variety of strings like:

• 5th century B.C.
• 325 B.C.
• Before 125 B.C.
• A.D. 96
• A.D. 410
• 5th century A.D.

As you can imagine, sorting on this column isn’t very useful. I can remove the sorting on this column but what I’d like is to be able to restore the table to it’s unsorted condition. That is, when the table is first displayed, the rows are in order by this date column. If a user then sorts by one of the other columns, the only way to get back to the original order is to reload the page. Is there some way to have a button or link that causes the table to be reordered in its default order?

Ideally, I’d be able to place this button anywhere and change the label. That would let me put it in the header for this date column and its effect would be to sort on that column, since that’s the default order of the rows.