Hróa þáttr heimska or the Tale of Roi the Fool is a short story (þáttr) from Iceland about a Dane called Hrói the Fool who is helped in a legal dispute by the wise old Swede Þorgnýr the Lawspeaker, and which takes place in the late 10th century.
In the version of Óláfs saga helga which is found in the Flatey Book, it is inserted together with Styrbjarnar þáttr Svíakappa in the description of Olaf Haraldsson's wooing of the Swedish princess Ingegerd Olofsdotter.
However, after the deal had been made and the goods delivered, Hrói came to fetch the merchandise, and discovered that Helgi had tricked him.
Helgi also stated that Hrói had broken the king's law by not guarding his goods, so that a thief might steal them.
He then met a beautiful girl called Sigrbjörg who had heard of him as Hrói the Fool, and she said that she was the daughter of Þorgnýr the Lawspeaker and that he was no friend of Helgi and his brothers.
He also asked her why she sighed so heavily and guessed that she had met Hrói and discovered that he was a good man.
However, Þorir did not agree on this procedure, and so Þorgnýr stated that those three men were wicked and unmanly and had too long weaved webs of lies around them.
Hrói then sentenced Þorgils and Þorir to death and banished Helgi from Sweden for life.