As an example of the Development of doctrine:
The Church has always and will always teach that Christ is present, Body and Blood, in the Eucharist. However, it was not until 1215 (Fourth Lateran Council? I’m not good on Council names but for osme reason that seems to be sticking out–I am probably wrong, knowing me), that the Church officially defined it, as well as using the word “Transubstantiation” to define the process of the bread and wine COMPLETELY changing into the Body and Blood.
Maybe that’s not what your looking for, but I think it is.