There are two big things to know about landsknechts: they dressed like circus clowns, and for most of a century, they beat the crap out of nearly everyone they faced on the battlefield. They weren’t the only ones dressed in brightly-colored clothes that had been slashed to floppy ribbons, but theirs tended to be the most brightly colored, most slashed, most floppy clothes around. Apparently the Holy Roman Emperor exempted them from sumptuary laws (which restricted clothing choices, among other things) on account of their ‘short and brutish’ lives..

Landsknechts mostly used pikes which, contrary to what years of video games taught me, are very long spears, not very long axe-things. They’d arrange themselves into big squares, several ranks deep, and move accross battlefields poking their enemies to death, with support from arquebusiers (men with early firearms called arquebusses) and higher-ranking landsknechts using six-foot long swords to bat down enemy pikes.

But back to the clothing.

Slashed clothing (see the dead soldier on the right, as well as on more or less everything Mr. Landsknecht is wearing) seems to have been inspired by the way clothing would look after a few hours on a blade-filled renaissance battlefield. Since soldiers are badass, all the boys in court started copying them, and soon you had delicately sewn-off patterns of ’slashes’ in doublets and hose (read: jackets and pants), usually with brightly-colored clothing underneath showing through. It’s sort of the early-1500’s version of, like, the $200, monogrammed, five-sizes-too-large jeans all the rich kids wore to look like badass rappers in the 1990’s. Landsknechts weren’t the only ones wearing slashed clothing, but you might say they were on the…cutting edge?

Incidentally, military uniforms have influenced a huge amount of our modern-day clothing. Ever wonder why they’re called trench coats or bomber jackets?

Codpieces, however, were not invented for the military, although they were super-popular for the first half of the 1500’s. It surprised me to learn they were invented for modesty’s sake. See, in the century or so beforehand, European men had taken to wearing pants that covered only their legs. They’d wear linen underwear, too, and men’s coats tended to be pretty long at this point, but things like sitting and riding horses could still give people an eyeful of man-parts. Enter the codpiece: a flap of fabric to cover your cod (“cod” is a middle-English word meaning scrotum or pouch, but the joke sort of works either way.)
But I guess boys will be boys, because within a few decades your average codpiece was padded and enlarged to such a degree that it might have been more modest to go nude. In closing, here is a link to these drawings of metal codpieces from Wikipedia, which I present without comment.