Emperor John V Palaiologos (1341-1391), minted circa 1341. Silver, 1.08g, 19mm.
Dumbarton Oaks
<a rel="nofollow" class="external text" href="https://www.doaks.org/resources/online-exhibits/byzantine-emperors-on-coins/doukas-lascarid-and-palaeologan-dynasties-1204-1453">Dumbarton Oaks</a>