For this reason he was frequently sent home from school for rest, and spent a large amount of his time walking over Cornwall and studying Cornish monuments and history.
Whenever he was able he would return to Cornwall and continue his historical research which in the early years was concerned very largely with the four western hundreds (Penwith, Kerrier, Pydar and Powder) but finally he planned a parochial history of the whole county on a grand scale.
A. R. Munro, the Rector of Lincoln College, Oxford; at the end of August, he set out with her for southern Italy.
He had been troubled for some months with pains in his chest and they attacked him severely at Monte Sant'Angelo on the Gargano, where he was visiting the shrine of the Cornish patron St Michael.
The collection includes 16,000 ancient documents, many hundreds of transcripts in Henderson's hand, and his own writings either in published form or in manuscript.