Today is the feast day of St Helen, the mother of the Emperor Constantine the Great, and the rediscoverer of the Holy Cross. There is an online biography of her here.
Coin of Flavia Iulia Helena, mother of Constantine I.
Æ Follis (19mm, 3.45 gm). Treveri (Trier) mint. Struck 325–326 AD.
The modern statue of the Emperor Constantine outside York Minster
In Orthodox iconography she is often depicted with Constantine, the Holy Cross between them, and this appears to have typology similar to images of Christ and the Virgin Mary, with, it might appear, the transfer of attributes and poses between both pairings. I am sure someone has written extensively on this subject, though I have not seen such work myself.