Title: Automatic Dictionary Generation: Could Brothers Grimm Create a Dictionary with BERT?. Abstract: The creation of the most famous German dictionary, also referred to as ``Deutsches Wörterbuch'' or in English ``The German Dictionary'', by the two brothers Jacob and Wilhelm Grimm, took more than a lifetime to be finished (1838--1961). In our work we examine the question, if it would be possible for them to create a dictionary using present technology, i.e., language models such as BERT. Starting with the definition of the task of Automatic Dictionary Generation, we propose a method based on contextualized word embeddings and hierarchical clustering to create a dictionary given unannotated text corpora.  We justify our design choices by running variants of our method on English texts, where ground truth dictionaries are available.  Finally, we apply of our approach to Shakespeare's work and automatically generate a dictionary tailored to Shakespearean vocabulary and contexts without human intervention.