Date Serial Number To Actual Date

I have a macro which copies the values from one cell to another. But, while copying the macro changes the date format to a serial number and this doesnot happen all the times. Below is the code I have. I want the macro to automatically convert the date from from serial number to dd/mm/yyyy. I tried quite a different ways, but none of them seems to work. Below is the macro I run to copy the contents from one cell to another.

Sub History()
'
' Macro: Backup results from prior rounds. Please run this macro after selecting the cell where the backup is to be done.
'
cur_row = ActiveCell.Row
If ActiveCell.Offset(-(cur_row - 10), 0).Value <> "History" Then
MsgBox ("Check whether the active cell is the designated history cell. History operation failed")
Exit Sub
Else
ActiveCell.FormulaR1C1 = ActiveCell.FormulaR1C1 & ActiveCell.Offset(0, -5).Value & " "..........................