More reading about HEMA you can find e.g. here:
HROARR – This is the largest collection of articles on HEMA right now. Some 50 HEMA instructors, researchers and practitioners have contributed with hundreds of articles. Additionally, the site also provides links to other clubs and organizations, equipment, and a library with manuals for download, and more. It is also run by our quarterstaff instructor Roger Norling, with some assistance from our Mattias Moberg.
Wiktenauer – This is a unique portal with transcriptions and translations of the majority of all known combat manuals from Europe and the periods that HEMA most commonly focuses on. Wiktenauer is, like HROARR, a non-profit site that rests on the charity work and commitment of practitioners, and there is a ton of material to enjoy and learn from.
Wikipedia om Historical European Martial Arts – This article somewhat simplified describes what HEMA is all about