When was Atgof y Ser created?

There is no known organization or entity called "Atgof y Ser". It's possible that the name is misspelled or refers to something very specific that I haven't been trained on.

Could you please provide more context or details about "Atgof y Ser"?

For example:

* Is it a company, a project, a book, or something else?

* Where did you encounter this name?

* Can you provide any other information about it?

With more information, I can try to help you find the answer you are looking for.