Christiana Marvin, Lady de Essex

Per FamilySearch.org, the parents of Christiana Marvin were Sir John Ramsey and Abigail Butler, and her husband was JOHN Marvin/Mervyn, which would be in agreement with the will of Roger Mervyn III, which states that his only son was named JOHN.

https://ancestors.familysearch.org/en/GDQC-RHZ/lady-christiane-of-e...

When Lady Christiane Of ESSEX Ramsay was born in 1455, in Washbrook, Suffolk, England, her father, Sir John Ramsay, was 25 and her mother, Abigail Butler, was 17. She had at least 1 daughter with John Mervyn. She died in 1503, at the age of 48.
Sincerely,

Judith Arnett