Aquestion about clical music recording?

ok so lets take a few of the greats of all time. Beethoven, Mozart, and Paganini. These composers were there during the 1600 and 1700 roughly. Now when u go to stores you can find Music CDs of these artists. I was wondering .... HOW?? I mean they didnt have any recording devices at those times right? So how did they record the original artists works ?