The Navigium Isidis or Isidis Navigium (trans. the vessel of Isis) was an annual ancient Roman religious festival in honor of the goddess Isis, held on March 5. The ancient festival of Navigium Isidis celebrated the Goddess Isis’s invention of the sail and her patronage of sailing that began each new sailing season.
Isis Euploia-Isis of Good Sailing-sailed with the crew of Ra on their journey through the underworld searching for the severed parts of her murdered husband Osiris. As the beloved Goddess of Alexandria, whose massive lighthouse guided ships far at sea to shore, Isis was invoked to protect all incoming as well as outgoing vessels. Akin to Yemanjk (February 9-10), Isis was worshiped at the shore and on the sea. She was considered the guardian of the grain ships that brought the bounty of Egypt to Rome. As her worship took root along the trade routes, seafarers would leave offerings and petition her protection before embarking on treacherous journeys.