The most common and most likely answer to this crossword clue is the 7 letter word KNEELED
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More clues leading to the result KNEELED
Buddy explains!

The straight part
We know that "as he did when knighted" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case as he did when knighted = kneeled.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does KNEELED mean?
KNEELED verb- To rest on one's bent knees, sometimes only one; to move to such a position.
- To cause to kneel.
- To rest on (one's) knees