"Seven white cats."
Translation:Saith cath wen.
cath is a feminine noun, so the adjective describing it, gwyn, has to be mutated -> wyn. Secondly, gwyn has a feminine form which is often used, gwen -> wen:
- cath wyn or cath wen - a white cat
Thanks for that! Is there a section where male/female/mutated adjectives is covered?