'cradle and grave' of Sergius's military reputation.

This seems to say that, although he did everything right, he will never be promoted.

SERGIUS (with grave irony). Madam: it was the cradle and the grave of my military reputation.

CATHERINE. How so?

SERGIUS. I won the battle the wrong way when our worthy Russian generals were losing it the right way. That upset their plans, and wounded their self-esteem. Two of their colonels got their regiments driven back on the correct principles of scientific warfare. Two major-generals got killed strictly according to military etiquette. Those two colonels are now major-generals; and I am still a simple major.

Explain the meaning of “the cradle and grave of my military reputation”?