Bryn Celli Ddu is a prehistoric burial place that dates back over 1500 years. Its name means ‘the mound in the dark grove’. It was plundered in 1699, and archaeologically excavated between 1928 and 1929. Norman Lockyer, who in 1906 published the first systematic study of megalithic astronomy, argued that Bryn Celli Ddu marked the summer solstice. The author, Coxe in 'Haunted Britain', states that the phallic symbols found here represent that some sort of fertility rites were performed there.