Responsa for Bava Batra 93:2

Q. A, the oldest brother in the family, who is in possession of his father's land, claims to have received it as a gift from him. He says that he was in undisturbed possession of it for many years before his father's death and for many years thereafter. Now his brothers want a share of the land. The local court decided in A's favor.
A. Since his brothers were young when their father died, A cannot claim undisturbed possession as proof of ownership for the period since his father's death, and must furnish documentary proof or witnesses to the effect that he enjoyed undisturbed possession for three years before his father's death.
SOURCES: Pr. 119; cf. Asheri, Sanhedrin 3, 37.

Q. A drained the water in his yard by means of a ditch which was adjacent to B's stone wall. B claimed that when the ditch was full, the water had flooded his house. He, therefore, demanded that A fill up his ditch. A claimed that the ditch had been in his yard for a period of twenty-four years and that B had never protested before. B, however, contended that the ditch had not previously caused him any damage. A's father bought the property with the ditch from a Jew who, in turn, had bought it from a Gentile.
A. If A removes his ditch one tefah from B's wall, he is free from further obligation. But even if A does not do so, he is free from any obligation since he inherited the ditch from his father, who, if alive, could claim that he bought the right to maintain the ditch from B. Moreover, A is not required to take an oath to the effect that he never heard his father say that he did not buy from B (or B's father) the right to maintain the ditch for the following reasons: a) Orphans are not required to take an oath in order to free themselves from a money obligation; b) the oath of orphans is a rabbinical decree and the Rabbis did not decree anything disadvantageous to the interests of the orphans.
The fact that A's yard originally belonged to a Gentile, has nothing to do with the case since B does not claim that the Gentile dug the ditch illegally. If B does put forth the claim that the Gentile dug the ditch illegally, it will avail him nothing, since, again, the court will have to put forth the claim, for A's benefit, that A's father bought the right to maintain the ditch from B or B's predecessors.
This Responsum was sent to R. Manahem b. David and R. Hillel b. Azriel of Würzburg (Cr. 23).
SOURCES: Cr. 23; Pr. 143; L. 388; Mord. B. B. 548; Agudah B. M. 180.