Jacobusdt assembled an excellent timeline building tool for Excel. Since I don’t use Excel I can’t test it but It sure does look useful.
I have included the instruction in the first sheet of the spreadsheet. I think it should be sufficient for most people who have previously been slightly exposed to Excel.
The development was done in MS Excel 2003 as this is the software to which I have access and can not guarantee it would work on later versions. I would appreciate it if you can ask someone to test it on a later version and give feedback to me.