So first you want to start with the hidden story. What’s the message you want to get across, figure out what your topic is and what you want to say about it. Second you have to break the hidden story down, what are the most important characters or aspect of the story. These will become the main characters, settings and events in your allegory. Third you have to pick a theme for the surface of the story and find correlations. The surface story should be different from the hidden story. Science fiction and fantasy work well.
Animals being in captivity is bad for their instincts. In captivity, animals lose their more wild side that's in touch with their original and natural environment. Unless an animal (specifically whales in this case) is injured and cannot be in the wild, they should not be kept in captivity.
The effective use of metaphor was most valuable to Aristotle. As metaphor, it is understood a figure of speech which provides a rhetorical effect by mentioning one thing in reference to another. it might compare two things which are different.
Yes the truce of Bordeaux was signed in 1357