Although there is seemingly no evidence for this, according to Zythophile, the generally accepted story is that after the passing of the Trademark Registration Act of 1875, when applications to apply for trademark registration opened on January 1, 1876, a Bass employee was sent to wait overnight outside the registrar’s office the day before in order to be the first in line to file to register a trademark the next morning. That’s why in 2013 Bass Pale Ale was renamed as Bass Trademark No.1.
This PDF mentions that the Guinness harp is another well known trademark registered in 1876. Of course, registration is a different thing from when a design was first used.
Other brands are mentioned in a list of the ten oldest company logos, such as Shell, Stella Artois, Levi Strauss, Heinz, Peugeot, and Prudential, but I can’t vouch for the dates listed. Via Brand New.
And in his recent chat about why logos endure, Michael Bierut said he thinks the earliest known logo is the Bass triangle.
I guess we’d have to say that there’s a big difference between a trademark and a registered trademark, and the former is very much older than the latter.
There is evidence of fixed typographical cyphers used by traders as identifiers in Ancient Greece. Logos are really a part of all human cultures of power, whether we’re talking about businesses or the symbols of royal houses. By the Middle Ages, the company logo was exactly what it is today: not only logos for businesses, but also individual logos for the products produced by a business, designed to be suggestive of esoteric qualities appealing to particular customers.
The Bass logo is the oldest trademark, but only in Great Britain. Previously, the Czech trademark PILSNER (1859) and American trademark (1870) were registered. I wrote an extensive article on the topic: The oldest registered trademarks in the world.