“Trademarks, or devices with the function of a trademark, have existed for at least 5,000 years. Some, such as ceramics marks, continue to be used today; others, such as heraldic marks, are often quoted or paraphrased in modern designs. Even the idea of visual pun on a name was used in ancient canting arms. Historically, trademarks have been primarily ‘senders’ marks, which are more concerned with the person sending them than the receiver.” (pp. 15)
(...) Perhaps, the first ‘graphic’ identification mark was an owner’s mark. It may have been a simple sign that a weapon belonged to a particular man.” (pp. 16)

MOLLERUP, Per — “Marks of Excellence: The history and taxonomy of trademarks”. London : Phaidon Press Limited, 1997. ISBN 0-7148-3838-1