Hreða Lore From Bede's The Reckoning of Time translated by Faith Wallis
Chapter 15: The English Months
In olden times the English people --for it did not seem fitting to me that I should speak of other nations' observance of the year and yet be silent about my own nation's-- calculated their months according to the course of the Moon. Hence, after the manner of the Greeks and the Romans, [the months] take their name from the Moon, for the moon is called mona and each month monath.
The first month, which the Latins call January, is Giuli; February is called Solmonath; March Hrethmonath [...]
Hrethmonath is named for their goddess Hretha, to whom they sacrificed at this time.
Note: In Teutonic Mythology Jakob Grimm presents evidence that in some parts of Germany the old name for March was Retmonat or Redtimonet, names which seem to be directly cognate with the Anglo-Saxon. This is the only evidence we have that the goddess Hreða was known outside of England.