Complex sentence: Fletcher's sole authorship of the play was specified during the seventeenth century by his friend Sir Aston Cockayne; since Fletcher's distinctive pattern of stylistic and textual preferences is continuous through the text, his authorship is not questioned.
Split into simpler sentences: Fletcher's sole authorship was specified during the 17th century by his friend Sir Aston Cockayne. It displays Fletcher's distinctive pattern of stylistic and textual preferences throughout the text, his authorship is not questioned.