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