How many letters does the top answer for “author of don quixote” have?

The most common answer is cervantes (9 letters).

Crossword clue: author of don quixote

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

cervantes 9 letters wd-fact-v3

Spanish writer best remembered for `Don Quixote' which satirizes chivalry and influenced the development of the novel fo

petipa 6 letters wd-fact-v3

author of don carlos 50% similar → schiller

author of don juan 50% similar → byron

author of don quichotte 50% similar → massenet

wrote don quixote 50% similar → cervantes, petipa