Complex sentence: In turn France gained the return of its sugar colony, Guadeloupe, which it considered more valuable than Canada, which Voltaire notoriously dismissed as "Quelques arpents de neige", "Some acres of snow".
Split into simpler sentences: In turn France gained the return of its sugar colony, Guadeloupe, which it considered more valuable than Canada. Voltaire had notoriously dismissed Canada as "Quelques arpents de neige", "Some acres of snow".