The venerable church of St. Helen is situated on the eastern side of the street, standing back and approached by an archway. Popular tradition ascribes its origin to the Emperor Constantine in honour of his mother, which is doubtless an error, but it unquestionably dates from the Saxon age, as in 1010 the relics of King Edmund the Martyr were temporarily deposited within its walls, when brought from East Anglia, to prevent their desecration at the hands of the Danes. In the twelfth century the advowson appears to have been held by one Ranulph, as in the reign of Henry II., _circa_ 1180, he and his son, Robert Fitz-Ranulph, made a grant of it to the Dean and Chapter of St. Paul's Cathedral. About half a century later, _circa_ 1212, William Fitz-William, a London goldsmith, and ancestor of the extant Earls Fitzwilliam, founded in connection with it a priory for nuns of the order of St. Benedict, which was dedicated to the Holy Cross and St. Helen, the prioress on her election to swear fealty to the Dean and Chapter, who transferred to the priory the advowson of the church. The church seems originally to have had simply a chancel and nave, without transepts or aisles, but when the priory was attached, it was duplicated by building another nave, and thus presented the appearance of a double-aisled church without an intermediate nave. A wall of division ran along the middle, one of the aisles being appropriated to the parishioners and the other to the nuns. It is to be feared that the fair inmates of the nunnery were not always very strict in their devotional exercises and seclusion from the outer world, and were even sometimes so naughty as to be subjected to punishments, one of which was being shut up in the crypt, which still exists, with the gratings, through which they could hear the service of the church without being present. Reginald Kentwode, dean of St. Paul's, in his periodical visitations, found so many "defautes and excesses" that he felt constrained to draw up a fresh code of rules for the regulation of the house, the original of which is amongst the Cotton MSS. in the British Museum. Willyam Basynge, Sheriff of London, 1309, added considerably to the buildings, and came to be regarded as the second founder. The seal of the priory was an oval, representing the Empress Helena standing by the cross (which she found in the Holy Land and brought to Europe) with the nails in her hand, and on the opposite side worshippers in the act of adoration. An impression of it is pendant from a deed in the possession of the Leathersellers' Company, and an engraving of it is given in Malcolm's _London Rediv._, vol. iii., p. 548.