The Polycomb Repressive Complexes(PRCs) target genes governing cell identity in mammals and can maintain a stable 'memory' of gene activity, with dysfunctions associated with embryonic lethality or developmental abnormalities. Although components of the Polycomb system have been identified and characterized over the last decades, we still do not understand how this property of memory is established. This deficiency arises from a lack of quantitative insight into the complex interplay within the system. To address this, we apply multiplexed imaging technology and synthetic biology tools to provide quantitative insight into the Polycomb memory system.