Slate has a very interesting article on this most basic of eatin' irons - or, at least, what I had thought was the most basic of them. Turns out it was actually the last to be developed, after the knife and spoon, so it's not so basic after all! Here's an excerpt.
Perhaps the fork is potent and intriguing because it is surprisingly modern. Humans got along just fine without forks for thousands of years. Which means we are, in a sense, still learning to use this small instrument. And our changing fork habits can reveal our attitudes about big subjects, including religion, masculinity, and foreignness.
The fork is a latecomer to the table. Knives are the descendants of sharpened hand axes—the oldest human tools. It is likely that the first spoons derived from whichever local objects were used to scoop up liquid: The word for spoon in both Latin and Greek derives from a snail shell while the Anglo-Saxon spon means chip. The shape of the fork has been around a lot longer than the eating utensil. In ancient Greece, Poseidon brandished a trident while mortals had large forked tools to pull food out of boiling pots. But the fork didn’t have a place at the Greek table, where people used spoons, knife points, and their hands.
. . .
In the Middle Ages, most people ate off rounds of stale bread called trenchers, which could hold cooked meat and vegetables and which could be brought directly to the mouth; knives and spoons could handle anything else that a hand couldn't. Forks, having journeyed to Italy from Byzantium, arrived in France along with Catherine de Medici, who traveled in 1533 from Italy to France to marry Henry II. The political culture of 16th-century France was riven by sectarian violence, and Catherine, in her role as mother to two child-kings, used massive public festivals to demonstrate the power of the monarchy. Food was part of this strategy of spectacle. Catherine's eating methods, as well as foods as diverse as the artichoke and ice cream, went on display as she toured the country for more than a year in the 1560s, drumming up support from the populace and devising etiquette that forced members of rival factions to eat together at her table.
Steel French forks dating from late 1500's to early 1600's
At this time, most forks were two-pronged, and either hefty enough to hold down a cut of meat (similar to what we would think of today as a carving fork) or so dainty they were used primarily to eat sweets at the end of meals. Forks were used occasionally, but not every day. Montaigne, writing in the 1570s in a passage about the force of habit, mentions forks but says he rarely uses them. And they were still associated with sinister behavior. In an essay in Feeding Desire on the sexual politics of cutlery, Carolin Young notes that in 1605, an anonymous allegorical novel about the courtiers of Henry III portrayed a mysterious island peopled by hermaphrodites, whose behavior is characterized by theatricality, artifice, and falsehood. Sure enough, the hermaphrodites eat with forks, spilling more food than they manage to consume in their pursuit of the new and the unnecessary. Young traces the “unsettlingly effeminate aura” of the fork all the way through 1897, when British sailors are still eating without forks, considering them to be unmanly.
There's more at the link. Quirkily entertaining! (And, for those interested, the 'trencher' referred to in the extract above is the root of the term 'trencherman', referring to someone who enjoys his food in abundance.)