In a world where it was difficult to obtain information and verify reputation, seals like this one were a tangible way to convey security, legitimacy and trust. They were also extremely difficult to forge.
When business people saw the Bank of Montreal corporate seal on a document, they knew immediately what it meant and who stood behind it. It represented a promise and a guarantee.
Corporate seals were, and in many cases still are, used to certify official documents, deeds and acts of the bank.