I don't know what happened, but I have lost almost all of my apps - from my 1st gen IPad. Since owning my tablet I have purchased a fair number of apps from the App store.
I can't remember, right at this moment, every title that I had either bought, or freely downloaded, but can see that there is just one of my apps on my IPad.
Fooling around with ITunes has almost always been a problematic event for me, and it was after integrating my IPad with ITunes, the other day, that I lost my apps. Now, I can't see how to go about getting them back. I can go to the app store, for the titles that I can remember, and download them again, but I (as already mentioned) cannot remember all of the titles. If, and when I am able to get this matter back in hand, I will Do what I can to see that I NEVER fool with Itunes again.