Complex sentence: In 1823 however Stannard was in a severe financial crisis which was temporarily alleviated by the patronage of John Harvey who commissioned him to paint what is Stannard's masterwork,' Thorpe Water frolic-afternoon'.
Split into simpler sentences: In 1823 however Stannard was in a severe financial crisis. This cris was temporarily alleviated by the patronage of John Harvey who commissioned him to paint what is Stannard's masterwork' Thorpe Water frolic-afternoon'.