I want to know the answer to the following question:
Which word in the phrase "het jaar des Heren" is a weak noun with a genitive ending added?
All the background I'm provided with is that "In such lexicalized expressions remnants of strong and weak nouns can be found too, e.g. in het jaar des Heren (Anno Domini), where "-en" is actually the genitive ending of the weak noun.". Is that enough to answer the question?
Answer: yes