Original sentence: It has been suggested that the island was first explored by the Portuguese navigator Pêro de Mascarenhas (1470- June 23, 1555) during his voyage of 1512-13, but there is little corroborative evidence for this, while cartographic analysis points to a subsequent date, possibly 1532 or later
Edited sentence: It has been suggested that the island was first explored by the Portuguese navigator Pêro de Mascarenhas (1470–June 23, 1555) during his voyage of 1512–13, but there is little corroborative evidence for this, while cartographic analysis points to a subsequent date, possibly 1532 or later