St. Constantine (272 – 337) was an emperor of the Roman Empire and eventually refounded Byzantium with Constantinople (Constantine’s city). He was the first Roman emperor to endorse Christianity and called the First Ecuminical Council (to refute Arianism). St. Helen (255 – 330) was his mother. She went on a pilgrimage through the Holy Land in an effort to identify holy sites, destroy the pagan temples there and establish churches in their places. She is credited with finding the Life Creating Cross (a good story, to be found here). [More about Sts. Constantine and Helen here.]
Many Years to all of our Helens (and Ellens, Elenas, Elenis, Elaines, Eleanors, Elinores, Yelenas, Helenas, and Ellas) and to all of our Constantines (and Costas and Guses)!