This stitch is called by everyone Jacobean Couching, but everyone also seems to have another name for it, like Laid Filling or Trellis Stitch. This stitch is one of the classic crewel embroidery stitches. It creates a nice patterned filling stitch and is often used in stitching larger areas.
There are three steps to this stitch, making a grid of long stitches which can be either upright or at an angle, anchoring down the long stitches at the intersections, and making a filling stitch in the grid's squares or diamonds. Actually the filling stitch is optional, but it's very common to have one.
It's straightforward enough to make the grid. Making an upright grid is easiest, the diagonal grids can be a real challenge, since it's so easy to change the angles.
I hope this lesson was useful! There will be a little project to stitch at the end of this Fall Stitch School lesson, so you can practice a bit of crewel embroidery yourself!