The loose assemblage of stories current in Iceland before the Sagas were composed in writing must, of course, have been capable of all kinds of variation. The written Sagas gave a check to oral variations and rearrangements; but many of them in extant alternative versions keep the traces of the original story-teller's freedom of selection, while all the Sagas together in a body acknowledge themselves practically as a selection from traditional report. Each one, the most complete as well as the most disorderly, is taken out of a mass of traditional knowledge relating to certain recognisable persons, of whom any one may be chosen for a time as the centre of interest, and any one may become a subordinate character in some one else's adventures. One Saga plays into the others, and introduces people incidentally who may be the heroes of other stories. As a result of this selective practice of the Sagas, it sometimes happens that an important or an interesting part of the record may be dropped by one Saga and picked up casually by another. Thus in the written Sagas, one of the best stories of the two Foster-brothers (or rather "Brothers by oath," _fratres jurati_) Thorgeir and Thormod the poet, is preserved not by their own proper history, _Fóstbræðra Saga_, but in the story of Grettir the Strong; how they and Grettir lived a winter through in the same house without quarrelling, and how their courage was estimated by their host.[48] [Footnote 48: "Is it true, Thorgils, that you have entertained those three men this winter, that are held to be the most regardless and overbearing, and all of them outlaws, and you have handled them so that none has hurt another?" Yes, it was true, said Thorgils. Skapti said: "That is something for a man to be proud of; but what do you think of the three, and how are they each of them in courage?" Thorgils said: "They are all three bold men to the full; yet two of them, I think, may tell what fear is like. It is not in the same way with both; for Thormod fears God, and Grettir is so afraid of the dark that after dark he would never stir, if he had his own way; but I do not know that Thorgeir, my kinsman, is afraid of anything."--"You have read them well," says Skapti; and so their talk ended (_Grettis Saga_, c. 51).]