I want to know the answer to the following question:
In what century long before Dutch did most West Germanic dialects probably lose case inflection?
All the background I'm provided with is that "The Dutch written grammar has simplified over the past 100 years: cases are now mainly used for the pronouns, such as ik (I), mij, me (me), mijn (my), wie (who), wiens (whose: masculine or neuter singular), wier (whose: feminine singular; masculine, feminine or neuter plural).". Is that enough to answer the question?
Answer: no