The past tense of cost is usually “cost”.
Very rarely is the past tense “costed” used, it’s more common to just say cost.
Answer:
When he left the stricken city, he had put Secretary of War Henry Knox in charge of the government, giving the former general clear instructions to report to him weekly concerning the spread of yellow fever. But after a few days' close contact with the pestilence, Knox found that his warrior instinct had abandoned him.
