Responsa for Bava Metzia 55:17
במקדש ראשון דנפישי ישראל טובא דכתיב בהו (מלכים א ד, כ) יהודה וישראל רבים כחול אשר על הים לרוב בעינן כולי האי במקדש שני דלא נפישי ישראל טובא דכתיב בהו (עזרא ב, סד) כל הקהל כאחד ארבע רבוא אלפים שלש מאות וששים לא בעינן כולי האי
<b><i>MISHNAH</i></b>. NOW, UNTIL WHEN IS HE [THE FINDER] OBLIGED TO PROCLAIM IT? UNTIL HIS NEIGHBOURS MAY KNOW THEREOF: THIS IS R. MEIR'S VIEW. R. JUDAH MAINTAINED: [UNTIL] THREE FESTIVALS [HAVE PASSED], AND AN ADDITIONAL SEVEN DAYS AFTER THE LAST FESTIVAL, GIVING THREE DAYS FOR GOING HOME, THREE DAYS FOR RETURNING, AND ONE DAY FOR ANNOUNCING.<span class="x" onmousemove="('comment',' The three Festivals referred to are Passover, Weeks, and Tabernacles, when Jerusalem was visited by all Israel. This was the practice whilst the Temple stood and some time after; but v. Gemara on this. ');"><sup>15</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.