Coats of Arms used today are a relic of former times when the bulk of the population could not read. Then they recognised ownership, authority or even the contents of a shop by pictorial representation, that is the badge or arms hanging outside it.
The Arms appear to have been granted to St. Ives when it was incorporated as a Borough. An extract from the 1874 Charter of Incorporation reads as follows
"AND we do further will, grant and declare that the said Mayor, Aldermen and Burgesses of the Borough of Saint Ives and their successors shall and may forever hereafter have a Common Seal to serve them in transacting their business, and also shall and may use and assume armorial bearings and devices, which shall be duly entered and enrolled in the Herald's College"
However that does not mean to say that the town did not have a Coat of Arms before that. One must remember that the town largely belonged to the Duke of Manchester or the Bishops of Ely before that and their representatives may have used Seals and Arms supplied by them.
