Currently Being ModeratedMar 14, 2013 4:34 AM (in response to Jmh2013)
Unfortunately that historical data also chews up memory
If you sync through iTunes, connect your iPad and open iTunes. Navigate to the info tab and you'll see a 'do not sync events older than....' box. I think the default is 30, 60 or 90 days. Change it however long you want.
Just bear in mind that calendar info is part of what makes up the 'other' part of your memory usage. More data you keep, more room it takes, so you may need to manage you need for history with your need for space.