The ravens on the sail ship

Here's Lisbon's coat of arms and a small explanation of it's meaning:

"The image on the coat of arms commemorates the transfer of the relics of Saint Vincent of Saragossa [...] to Lisbon. According to legend, after he was martyred, ravens protected St. Vincent's body from being devoured by wild animals, until his followers could recover the body. [...] King Afonso Henriques (1139?1185) [...] brought it by ship to the Monastery of São Vicente de Fora in Lisbon, still accompanied by the ravens."

(from Wikipedia)