Responsa for Bava Metzia 55:16
אמר רב יוסף לא קשיא כאן במקדש ראשון כאן במקדש שני
— But it had a perforation at the side of a certain letter. If he identifies the ribbon [with which the divorce was tied], and she does likewise, it must be given to her. Wherewith [is it identified]? Shall we say, by [its colour], white or red? perhaps she saw it whilst he was holding it! — Hence, by its length. If he states, [it was found] in a valise, and she states likewise, it must be surrendered to him. Why? She knows full well that he places whatever he has [of his documents] in a valise.<span class="x" onmousemove="('comment',' Though this does not prove his ownership either, it must nevertheless be surrendered to him, since she cannot be declared free after a valid doubt has arisen. ');"><sup>14</sup></span>
Teshuvot Maharam
A. There is no contradiction. R. Tam means to say that whenever a person would be entitled to collect his claim were he to take an oath to support it, such an oath would not be required if he obtain the testimony of a single witness supporting the claim. Thus, the testimony of a single witness directed against a litigant has the effect of requiring an oath (denying the truth of such testimony) when otherwise no oath would have been required; and such testimony in favor of a litigant has the effect of rendering unnecessary an oath that otherwise would have been required. However, when two persons lay claim to an object found by a third and both give the proper identifying marks, no oath is accepted from either of the claimants and the object is not delivered to either of them. Therefore, the additional testimony of a single witness does not change the situation.
This Responsum is addressed to: "My teacher, and relative, Rabbi Menahem", of Würzburg.
SOURCES: L. 343; Mord. B. M. 417; Tesh. Maim. to Mishpatim, 6; Asheri B. M. 1, 3. Cf. Terumat Hadeshen 334.