I believe the answer is:
ITALIAN COMPOSER OF THE RED PRIEST 'ITALIAN COMPOSER OF THE RED PRIEST' is a 29 letter phrase starting with I and ending with T Crossword clues for 'ITALIAN COMPOSER OF THE RED PRIEST'. 'ITALIAN COMPOSER OF THE RED PRIEST' is a 29 letter phrase starting with I and ending with T Crossword clues for 'ITALIAN COMPOSER OF THE RED PRIEST' Synonyms, crossword answers and other related words for ITALIAN COMPOSER OF THE RED PRIEST vivaldi. The Baroque Bohemians.
'he composed' is the definition.
(composer Antonio Vivaldi)
'line in exam papers the wrong way' is the wordplay.
'line' becomes 'l'.
'in' means one lot of letters goes inside another.
'exam' becomes 'viva' (short for 'viva voce', an oral examination).
'papers' becomes 'ID' (identification papers).
'the wrong way' is a reversal indicator.
'id' reversed gives 'di'.
'viva'+'di'='vivadi'
'l' inserted within 'vivadi' is 'VIVALDI'.
(Other definitions for vivaldi that I've seen before include 'Italian composer, Antonio (d. 1741)', 'Venetian composer ('The Red Priest'), d. 1741', 'Italian composer of 'The Four Seasons', 'Italian composer (the Red Priest) , d.1741', 'Baroque Venetian composer, d.1741'.)