Robert M Watson Jr
The 'textbook' of Publius Flavius Vegetius Renatus http://www.pvv.ntnu.no/~madsb/home/war/vegetius/
Wikipedia has some interesting info on the work and the man ... strange echoes can be heard.
Tangent: spears made with fire sharpened points have been found and dated ~400,000 years of age. Seems that any srious budoka should know a thing or two about how to handle a spear.
.....100 days for spear
...1000 days for bow
10,000 days for sword
For our particular interests in power and aiki; Spear teaches many things, but sword remains the hardest and most complete.