Further to RiotGibbon’s post, I found this in Peter Ackroyd’s “London the Biography”:
In the records of St Paul’s Cathedral the adjacent buildings are known as ‘Camera Dianae’. A 15th century chronicler recalled a time when ‘London worships Diana’. She was the goddess of the hunt, so perhaps linking with the ceremony “that took place at St Paul’s as late as the 16th century: a stag’s head was impaled on a spear and carried about the church; it was then received upon the steps of the church by priests wearing garlands of flowers upon their heads.”