The most prevalent period images of knitting actually come in the form of the "Knitting Madonnas". In Catholic countries, it seems to have been a meme to paint the Virgin Mary (or one of her thematic surrogates) knitting or holding implements of knitting/spinning. Some of my favorites show her apparently trying to take her knitting tools back from a Christ child that's acting like a very human baby and playing with the spinning wand or whathaveyou.
I can't imagine why I feel a link to the Madonna trying to knit/spin with a fussy baby on her lap trying to "help"...
This house is overrun with yarn gremlins.
Here's a "Knitting Madonna" care of the Wikimedia Commons that pushes my start date for knitting 'in the round' from mid-1500's back into the dawn of the previous century as some of you were kind enough to point out.
I most certainly stand corrected on that point. (Click image to embiggen.)
And here are some "Spinning Madonnas" for you to ponder over on the Spinning Fishwife blog. (Hat tip to Kat Porter for that link!)
The Purl StitchIn order to make the tidy, clothlike 'stockinette' stitch that seems to dominate period knitting, you have to know how to make rows of knit and alternating purl stitches. Which means learning to purl.
This is how we begin the knit stitch. Note that the needles are going through the loop of yarn in the same direction. The active needle (the right if you are right-handed, left if you're a southpaw) is behind the carrying needle (the needle carrying the previous row when you begin).
These are my terms. I don't know how everyone else thinks of these things, but they fit how I see this process, so I'm going with it.
The "throw" is once again between the two crossed points, only this time passing in front of the carrying needle.
Once again, you use the point of your active needle to pick up the thrown yarn and pull it through to create a loop...
When you ease the loop off the carrying needle onto the active needle, you've created your first purl stitch!
Excellent! Now, keep going. I learned that stitch this morning and at this point, I've done a sum total of about eighty of them. Which isn't very many. Much more practice will be needed to create the kinds of beautiful knitted garments my beloved Engineer is capable of.
When you work alternating rows of knit and purl, the "right side" of your fabric creates that nice, flat, woven aspect that you see in so many sweaters, stocking caps, socks, and knitted whatnot.
Keep that trailing thread wrapped around your pinky or something, because loosy-goosy knitting isn't worth much in terms of warmth or aesthetics.
These are the two key stitches we're going to use to make our first knitted item. Straight out of Shakespeare: it's a Monmouth Cap!