In the 1920s, Casson and fellow Group of Seven artist Franklin Carmichael worked to revive watercolour as a serious artistic medium, and in 1925 they founded the Canadian Society of Painters in Water Colour. A pivotal Lake Superior sketching trip with Carmichael in 1928 brought Casson’s technique to its peak, and upon their return, the two artists successfully lobbied for a dedicated room for watercolours in the 1930 Group of Seven exhibition. The eloquence of these works proved a resounding success. As biographer Paul Duval writes, “His compositions had acquired a sure formalization, his washes were laid with a consummate assurance, and the boldness of his colour revealed a brilliance and depth then rarely seen in the medium.” This 1947 watercolour demonstrates a confident and sophisticated handling of the medium, as Casson creates an impactful portrayal of the island-dotted landscapes around Killarney and Manitoulin Island. With meandering bays and rolling hills, the composition is quintessential Casson—a stunning vista imbued with harmony and tranquility.