Matthew Walker

10 strand Matthew Walker + 5 strand plait
Philip Le Masurier
I'm reading Post Captain by Patrick O'Brian (page 210) and he mentions that one of the seamen is a fine hand at the Mathew Walker knot and here we are.

The video starts with a simple braid, but that only takes a couple of minutes, the rest of video is devoted to tying the Mathew Walker.

Wikipedia tells us:

The traditional use of the knot is to form a knob or "stopper" to prevent the end of the rope from passing through a hole, for instance in rigging the lanyards which tension the shrouds on older sailing ships with standing rigging of fiber cordage.

Wikipedia also has a story about how the knot got its name.