One of the most significant anniversaries this year is one of importance in the history of Christianity, but has passed with relatively little notice. The beginning of this month saw the 1700th anniversary of the Edict of Milan,as dated by tradition, by which Christianity was permitted alongside other religions in the Roman Empire. However, there has been an exhibition conceived and designed by the Archdiocese of Milan in the city to celebrate the event, Constantino dC 313, at Palazzo Reale which finishes on the 27th March and moves to the Curia Livia in Rome in April. The exhibition looks at the events which led to the legalisation of Christianity and other religions, at the founding of Mediolarum (Milan) in the 4th c AD, and at the beginnings of Constantine’s own promotion of Christianity, which followed his victory in battle under the banner of the Chrismon symbol at the Milvian Bridge. The symbol is based on the intersection of two letters from Christ’s name Xhi-Ro. The exhibition traces the growth in the use of the symbol as Christianity spread through the Empire. There is also a large section on the mother of Constantine, St Helen, who became a pilgrim to Jerusalem and the Holy Land and is believed to have found the True Cross. She is also credited with establishing the basilicas on the site of the Nativity in Bethlehem and the Crucifixion and Resurrection in Jerusalem, which had by then both become pagan shrines intended, ironically, to eradicate their original significance. Included in the exhibition is Cima’s painting of St Helen from the National Gallery of Art, Washington.