Who is Josephine Bowen Holman from Thunderstruck and what is their importance?

Josephine Bowen Holman is an heiress, who is originally from Indianapolis. She meets Marconi in 1899 on a transatlantic ship, after which, they become engaged for a short period of time. Their engagement is eventually broken off because Marconi is preoccupied with his wireless experiments and has little time for a romantic relationship.