Stem Stitch as indicated by Therese deDillmont in her "Encyclopedia of Needlework" originally published about 1870.

This technique requires going back to where the first stitch went down, but two threads above.

This type of stem stitch is often referred to as Wide Stem Stitch and can be made even wider by angling the needle farther up (3, 4 or more threads above the previously ended stitch). Or, starting a thread or two below the line of stitching and coming up a thread or two above the line in a manner as shown below.

Note that each stitch is over 4 threads and comes back 2 (halfway), but the return is up (needle travels at an angle) 2 threads above the line where the last stitch ended.

A.  Up at 1
B.  Down at 2 up at 3
C.  Down at 4 up at 5
D.  Down at 6 - repeat

On fine grounds, two threads up is not a great distance and there would be only a slightly noticeable slant to the stitch. On coarser grounds as indicated in the graphic at left and illustration above, those two threads create a much steeper angle.