Prima Materia practice
The Cult of the Black Madonna
The reverence for the Black Madonna (found in many Templar territories, like Chartres Cathedral) is an esoteric marker. It links the tradition back to the Earth Mother/Sophia/Isis current, representing the Womb of Wisdom from which Gnosis is born.
It is the Nigredo stage—the hidden, dark, alchemical beginning of the Work, containing the potential light.