The old painters used symbols that their viewers were familiar with. Do you paint for targeted audiences? If not what is your reason for using symbols the typical viewer won’t understand? Just curious.
I dabble in medieval manuscript illumination, miniatures and icons. In that day and age, painters were not so much celebrated for their "creativity" so much as they were their ability to adhere to rigid iconography and adherence to themes. In order to look "authentic" you have to borrow heavily from the illuminators and scribes of that age as they did from one another.