I've been using the calendar on my iPad 2 since October 2011, very happily. Suddenly all data from 2011 and the first two months of 2012 is gone (except for any items put in as all-day events). It now seems to only keep 30 day history. I've checked the "calendars" box in upper left corner where it says to "show all calendars" but still no history. It does show All Yahoo! While I do use Yahoo for my email I have never used Yahoo for calendars. Can't figure out how Yahoo got into the picture. I have gone to settings but don't see any place to correct this situation.