To Toe the Line: Origin and Meaning

What does to toe the line mean?
This is an interesting one. As usual there are multiple origins, but the meanings are all similar.
To control yourself or to do things in an acceptable manner.
The oldest reference is to things nautical. The spaces between deck planks on wooden ships were filled with a black substance called oakum. This made a visible line. When sailors were ordered to fall in on deck, they positioned their toes on the line to form a straight stripe.
Also nautical, was the procedure followed when sailors were punished. They were made to “toe the line” for long periods of time, in all weather conditions.
A further reference is to politics. Politicians in the British House of Commons carried swords to meetings. Lines were drawn between the opposing parties that were more than a swords length from each other. When things became heated they would be ordered to “toe the line”, in that way they could not cause grievous bodily harm. (Imagine politicians bearing arms in political meetings today)
Also from the 19Th Century the meaning was applicable to athletics. By toeing the line an athlete would gain no advantage over his opponent