[Aquinasfan]

I would like to remind everyone here that the addition of "filioque" was done to combat heresy and not to change the Creed.

In practice, most dogmas are promulgated in response to heresies.

It acquired a life of its own and was perverted into something that it never was by the Franks who, in ignorance and arrogance, accused the Greeks of committing "heresy" for omitting the "filioque"!

A development in doctrine isn't necessarily an error, is it?

[kosta50]

In practice, most dogmas are promulgated in response to heresies.

The local council of Toledo had no authoirty to make dogma. It's addition to the Creed was deemed "profitable" in combating Arian heresy and as such should have ceased when that heresy no longer existed.

A development in doctrine isn't necessarily an error, is it?

Doctrine is something the Church collectively decides in a Synod. It is certainly not the domain of a secular leader, a semi-iconoclast at that, to decide what is orthodox in the Church.