Mu'awiyah bin Abdullah (may Allah be pleased with them both) was informed by his father that he stopped at a place on a road of al-Sham and found a purse there containing 80 dinars. He mentioned it to Sayyiduna Umar (may Allah be pleased with him), and Sayyiduna Umar (may Allah be pleased with him) said: Announce it at the doors of the mosque, and tell whoever comes from al-Sham about it for a year; then when the year has passed, it is yours.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12090