Mischna zu Dewarim 19:15

These are subjects concerning which Beth Hillel changed their mind and taught according to the opinion of Beth Shammai:A woman who came from overseas and said: “My husband died” may be married again; “My husband died [without children]” she must be married by her husband’s brother (the levir). But Beth Hillel says: “We have heard so only in the case of one who came from the harvesting.” Beth Shammai said to them: “It is the same thing in the case of one who came from the harvesting or who came from the olive-picking or who came from overseas; they mentioned harvesting only because that is how it happened.” Then Beth Hillel changed their mind and taught according to Beth Shammai. Beth Shammai says: “She may be married again and take her kethubah payment.” But Beth Hillel says: “She may be married again but may not take her kethubah payment.” Beth Shammai said to them: “You have permitted the graver matter of a forbidden marriage, should you not permit the lighter matter of property?” Beth Hillel said to them: “We have found that brothers do not inherit on her statement.” Beth Shammai said to them: “Do we not infer it from her marriage document in which he writes to her ‘That if you be married to another you shall take what is written for you’?” Then Beth Hillel changed their mind and taught according to the opinion of Beth Shammai.