Jason steals the Fleece and dumps the girl. Easily an ad that could have run in the local Greek Star Gazette of the time. And here's the story it would have told. Well folks, at one point in his life, Jase decided to go a huntin' after a sheepskin whose hide was as large as a bull's and whose fleece was made of solid gold. The reason Jason did this was that he was told if he brought the gold back, he would be made king by the then ruling regent.
Life is full of kickers.
This fleece was guarded by a dragon and this dragon wasn't going to let anyone get their hands on the gold. Mr. Dragon knew a good thing when he had one. Jason tried all sorts of trick. Fact is, the dragon found Jason to be a tad insolent. Tact, was clearly not Jason's strong point.