A Crow caught in a snare prayed to Apollo to release him, making a vow to offer some frankincense at his shrine. But when rescued from his danger, he forgot his promise. Shortly afterwards, again caught in a snare, he passed by Apollo and made the same promise to offer frankincense to Mercury. Mercury soon appeared and said to him, 'O thou most base fellow? how can I believe thee, who hast disowned and wronged thy former patron?'