This is very neat idea Jesse. Do you mean that
Select[TextSentences[nlp], StringMatchQ[#, RegularExpression[".*?(?:I|i)n (\\d{4}).*?\\."]] &]
is more robust in finding sentences with year dates then given in blog method
TextCases[nlp, Containing["Sentence", "Number"]]
I am not that familiar with regex. Could you explain briefly how to read
RegularExpression[".*?(?:I|i)n (\\d{4}).*?\\."]