Possible Clues:

• Composer from Britain penning number one
• Tomaso —, Italian Baroque composer
• Italian composer; non-alibi (anagram)
• Composer of note in Britain and Ireland primarily
• Italian composer to whom a well-known adagio was attributed
• White man went over province - he made notes
• One of his works remains
• White man, note, with one composer
• Composer from Britain digesting Nielsen's First on island
• Composer making name in Britain and Italy