Almost all researchers are familiar with the concept of plagiarism these days. However, many scholars allege that plagiarism and its ethical ramifications are new western concepts that have not existed in scientific and literary history. In their opinion, using the ideas of others was allowed liberally in past academic and literary communities. I have presented the definition of "plagiarism" according to Shams-e-Qays, a great Persian literary scientist of the thirteenth century AD, to show that this is not the case and that the attitude towards plagiarism was even more strict in ancient times.