The new book, \“La Florida: Catholics, Conquistadores, and Other American Origin Stories\” opens with the story that takes place in what’s now Florida in the fall of 1565 when Spanish explorer Pedro Menéndez de Avilés celebrated a ‘feast day of commemoration’ with his men after their successful landing at the future site of the town of St. Augustine. This celebration had many of the same trappings as what we think of when we recount the story of the first Thanksgiving, celebrated 56 years later in the fall of 1621, by Pilgrims in Plymouth Plantation. But, it’s not considered the \“first Thanksgiving.\” Why is that?