Lucius Annaeus Seneca

Sometimes the routes leading to feelings of anger are so convoluted and circuitous that it takes enormous skill to discern their original source, or fountainhead. But regardless of the reason for or the source of the anger or the relative ease or complexity in perceiving either the anger or its source - everybody, but everybody, gets angry.

The idea of copyright did not exist in ancient times, when authors frequently copied other authors at length in works of non-fiction. This practice was useful, and is the only way many authors' works have survived even in part.