The early versions of the Amsterdam seal show a cog, on board a merchant with banner, a military man and a dog — representing trade, defense and loyalty. When Amsterdam got city rights in 1275, the city chose to display a cog on their seal.
The City Hall (now Royal Palace) on Dam square has a wind vane with a cog. The Prinsenhof (later City Hall and now Hotel The Grand) has a vane like that as well and so does the Rijksmuseum. There’s also one on the Stock Exchange at Beursplein 5. The Munttoren (Mint Tower) on the Muntplein has a gable stone showing a cog, placed there during a renovation in 1938-1939.
The Emperor’s Crown
A curious historic anomaly can be seen on the gable stones attached to the Accijnshuis (Tax House) on the Oudebrugsteeg corner with the Beursstraat: a cog with a French flag and an Amsterdam flag, above it the Emperor’s Crown. But Amsterdam had gotten the right to show the crown above their coat of arms (with the three crosses), not above the seal with the cog.
The right to carry the crown was given to Amsterdam in 1489 by Emperor Maximilian of Austria as a thank you for the big loans and military assistance Amsterdam had given him. Being able to display the crown above the coat of arms was much more practical than just symbolic: the Emperor’s protection was an important recommendation for Dutch traders abroad.
Cogs appeared from around 1200 on and were an adapted version of the Viking knarr ships — they had one sail from a mast in the center and often a partial deck. Cogs were seaworthy sailing wooden vessels, very wide, resembling a floating nutshell — they were slow and difficult to steer but had a huge loading capacity of around 80-200 tons. They could have a length of 15-30 meter (49-98 ft).
The rise in the use of cogs was related to the population explosion and the rise of cities in the late Middle Ages: more people meant more food, markets crossed borders more and more. From 1350 on cogs were mostly used for transporting bulk goods to and from ports on the Baltic Sea. Where the Hanse towns focused on luxury goods, the Dutch specialised in bulk goods like grain and wood, making Amsterdam the hub of the European grain market.
The trade with this area became so important that it was often referred to as “the mother of all trades” (moedernegotie in Dutch). It was actually largely responsible for the wealth in Amsterdam, even during the so-called Golden Century (Gouden Eeuw) the wealth did not come from the V.O.C. as much as it did from the route to the Baltic Sea. In fact, the first voyages to the East-Indies were financed largely with money from the Baltic trade.
Hulks instead of Cogs
By the time of the Dutch Golden Century (roughly from 1581 to 1672) the cogs had mostly been replaced by more modern vessels, but the cog was still used on seals as a symbol of trade. In reality though, from the 15th century on, cogs were phased out for another ship type, the hulk. These sailed to England (wool, tin and coal), France (salt, wine, subtropical fruits) and Bruges (wool and linen).