Why the English call French Frogs...

Although the Chinese and the Aztecs had frogs on the menu long before the French, the origin of the custom of eating frog legs in France, comes from a 12th century ban of meat by the Catholic clergy on certain days, but fish was permitted.

Monks who lived in the interior of the country and had no access to fresh fish, convinced the clergy that frogs were in the fish family and therefore were not meat. 

Seeing that all was well in the culinary department and the clergy accepted frogs as fish, peasants copied the monks and a new culinary tradition was born in France. This is probably the origin of the name given to the French people ("mangeurs de grenouilles", or "frog eaters").

According to Wiki, Queen Elisabeth I, called her beloved Francis Duke of Anjou, her little frog, because he was French.

But recently (2014) archaeologists discovered fragments of an 8,000-year-old charred toad leg one mile away from Stonehenge in Wiltshire, hinting that the English were feasting on frogs’ legs 8,000 years before the French. 

The remains which were found alongside fish bones at the site are the earliest evidence of a cooked toad or frog anywhere in the world, scientists say.