Responsa for Bava Batra 287:4

Q. A married a widow, B, and lived with her for eight years till her death. B had not taken the customary widow's oath regarding her ketubah due her from her former husband. When she married A she was not considered very rich and no one suspected that she owned more than the value of her ketubah. But, after her death, when A declared, under oath, to the community (leaders, probably for purposes of taxation) the value of his assets, it was discovered that he had inherited from B more than the value of her ketubah from her former husband. The heirs of the latter, therefore, demand that A return the excess to them.
A. If the valuables B brought to A were undistinguishable and no one recognized them as having belonged to B's former husband, A is free from obligation for five reasons. a) Even if the valuables B brought to A were worth more than the value of her ketubah, such valuables may not all necessarily have come from the estate of her former husband, for she might have received some gifts or found a treasure. b) Were B still alive she would have been obliged to take an oath [to the effect that she did not take from her former husband more than the value of her ketubah], but now that she is dead, A is free from the obligation of taking an oath, since he is not supposed to know his wife's affairs. c) A is not even required to take the oath of an heir — that B never told him, and that he did not know that she had received from the estate of her former husband more than the value of her ketubah — since the heirs of B's former husband are not positive in their claim. The heirs, however, may pronounce the ban (herem) in the synagogue against anyone who does possess such knowledge and does not reveal it. Such ban would include A. d) Whatever a person would have retained, had he taken an oath, his heirs may retain without the necessity of taking an oath. e) Some authorities require A to take the oath of an heir; but since many great authorities absolve him from such oath, and since A is in possession of the aforesaid valuables, the burden of proof is upon the plaintiff. For similar reasons A would be free from the obligation of taking an oath, even if some of the valuables brought to him by B were distinguishable and were recognized as having belonged to B's former husband, if the valuables thus recognized were in themselves not worth more than the value of B's ketubah. But, if the distinguishable valuables are in themselves worth more than the value of B's ketubah, A must return the difference to the heirs of B's first husband.
Q. Witnesses have testified to the effect that B and her former husband, C, had made a binding agreement that in the event of the death of one party, the surviving party would share the property with the heirs. After C's death, B settled with all of C's heirs, except the youngest, D, who was born after the drawing up of the agreement. D, therefore, is now pressing his claim.
A. D was entitled to his share even though he was born after the agreement was made, for in it B did not bestow benefits on anybody; she merely relinquished her rights to C's property up to a certain extent, and D later became heir to the relinquished property. However, A may claim that B brought him nothing from C's estate, or he may contend that B had already settled with D, and be free from obligation for the reasons enumerated above.
SOURCES: Am II, 17; cf. Hayyim Or Zarua, Responsa 86; ibid. 165; ibid. 191.

Q. A says that B's mother before her death instructed B to give A one Mina out of her possessions, since she had owed money to A's mother and did not remember whether or not she had repaid the entire sum. B denies having received such instructions from his mother, and further claims that A's mother owed him more than one Mina. But A has witnesses who testify that after his mother's death B admitted having received these instructions.
A. Since B's mother did not take the required oath regarding her ketubah, she had no property of her own; even the clothes she wore on week-days belonged to the estate. Consequently B is unable to carry out his mother's instructions. B is under no moral obligation to repay his mother's debt since the mother herself had not been pressed for payment.
SOURCES: Cr. 76.

R. Hayyim Eliezer apparently further exchanged extensive correspondence with R. Mordecai concerning R. Shemarya's decision in the case where a man placed a covering on the head of his daughter worth more than her dowry, as he brought her to the Huppah (the marriage canopy).