Apart from good old Mmenosyne, are there gods or goddesses of memory (or lack thereof) in any legendarium?
I couldn't find much more beside Meng Po and possibly Muninn, but they don't feel very... substantial.
1 Answer
The figure in Norse mythology you should look into is not Muninn, who is indeed a quite secondary character, but rather Mímir. Although he's not explicitly characterized as a "god of memory" in the sources at our disposal, he has been associated with memory, and more specifically with the Greek goddess Mnemosyne by several scholars, on quite convincing grounds.
First of all, the most widely accepted etymology for his name comes from the Proto-Indo-European verb *(s)mer- "to remember", from which also English "memory" and Greek "Mnemosyne" originate. For this reason, Rudolf Simek in his "A Dictionary of Northern Mythology", renders Mímir as "the rememberer, the wise one", while Bruce Lincoln in "Waters of Memory, Waters of Forgetfulness" simply renders it as "memory", calling Mímir "a wise giant, patron of memory".
Apart from his name, perhaps the most striking resemblance with Mnemosyne lies in the fact that both of them preside over a water source (a pool in the case of the Greek goddess, a well in Mímir's case) which gives supernatural knowledge (in the form of memory or wisdom), in connection with an otherworldly river (Greek Lethe and Norse Gjöll). You can read more on this in the aforementioned Bruce Lincoln article.
In the first volume of "Prolonged Echoes: Old Norse Myths in Medieval Icelandic Society", Margaret Clunies Ross further promotes the notion of Mímir as patron of memory and compares him to Mnemosyne. First, she stresses how his wisdom is emphasized in medieval sources, and how the concepts of wisdom and memory were interlaced in pre-literate societies (like the one that generated Old Norse myth).
Then, building in part on an argument introduced by Turville-Petre in "Myth and Religion of the North", she gives an interpretation of an episode of the Æsir–Vanir War in Snorri's "Heimskringla". In this story, the gods Mímir and Hœnir are sent as hostages to the enemy Vanir. When the Vanir realize that Hœnir is useless when Mímir is not present, they sense deceit and behead Mímir. Clunies Ross explains the story by identifying Hœnir and Mímir as personifications of thought and memory respectively.
As a side note, Lincoln also calls the Celtic goddess Rosmerta "patroness of memory" and derives her name from the same *(s)mer- root as Mímir. Her association with healing springs might even suggest a deeper connection with Mímir and Mnemosyne, but this is highly speculative, as the most widely accepted etymology for her name seems to be "carer" or "provider", and she is believed to be a goddess of abundance.
