What is the usual theme in a petrarchan sonnet?

The conventions of his Sonnet cycle are the lady, a golden-haired, proud woman who cruelly rebuffs her poet-lover, and the lover, who fears the lady's scorn and rejection but faithfully hopes for her love. He describes himself as alternately freezing and burning, like a ship tossed by the sea. He calls upon sleep to ease his cares and realizes that through his poetry his lady will be given eternal fame.