While exploring inland along the northern coast of Florida in 1528, the members of the Narváez expedition, including Álvar Núñez Cabeza de Vaca, found a Native American village near present-day Tallahassee, Florida whose name they transcribed as Apalchen or Apalachen [a.paˈla.tʃɛn]. The name was soon altered by the Spanish to Apalachee and used as a name for the tribe and region spreading well inland to the north. Pánfilo de Narváez's expedition first entered Apalachee territory on June 15, 1528, and applied the name. Now spelled "Appalachian," it is the fourth-oldest surviving European place-name in the US.
Try to answer this question if possible (otherwise reply "unanswerable"): When did the Narvaez expedition explore Florida?
1528