Complex sentence: For nearly a millenia, prior to the invention of printing or photographic reproduction, the process of multiple recension was the primary method of preserving literary, religious, and artistic traditions; and copying was the purview not of artists in training but seasoned veterans.
Split into simpler sentences: For nearly a millenium prior to the invention of printing or photographic reproduction, the process of multiple recension was the primary method of preserving literary, religious, and artistic tradition. Thus, copying was the purview not of artists in training but seasoned veterans.