Pilgrimage to the Island of Cythera is an example of fêtes galantes and was painted by the French artist Jean-Antoine Watteau, considered the greatest French painter of the 18th Century. Though his career was a brief one (he died at the age of thirty-six, perhaps of tuberculosis), he accomplished two things. First, he "revitalized" the style of art often referred to as "Baroque," or "Rococo." This style of art encompassed many forms and was popular for a number of years during the 1700s. With this art form...
...artists gave up their symmetry and became increasingly ornate, florid, and playful.
Watteau is also…
...credited with inventing the genre of fêtes galantes: scenes of bucolic and idyllic charm, suffused with an air of theatricality.
The style of fêtes galantes was in response to Watteau's desire to appeal to private patrons (who provided funding for the artist) as well as pleasing the Académie des Beaux-Arts, by which he hoped to be recognized. His new style of art did both of these things.
Watteau was able to get his paintings the highest ranking at the Académie and still flatter his buyers.
Fêtes galantes was an important aspect of the Baroque or Rococo artistic period; during this time the artists of Europe were concentrating more on "intimacy and personal pleasures."
In the 1760, the Baroque or Rococo style received harsh criticism when...
...figures like Voltaire and Jacques-François Blondel voice[d] their criticism of the superficiality and degeneracy of the art.
This signaled the end of the popularity of the Baroque or Rococo style of art in France— though it would later be praised, and is even now recognized as a major component in the development of art in Europe's history.
"fete galante" (elegant outdoor entertainment)
The first respondent is correct in her answer; fêtes galante illustrates images of courtly scenes in an idyllic country setting.
Watteau took about five years to finish the work, and submitted it as a reception piece to the French Royal Academy of Painting and Sculpture. The subject was considered avant garde, hence the expression "fête galante" was invented to describe it.
The Pilgrimage to Cythera is truly a masterpiece and allowed Watteau admission into the Academy as a painter of "fêtes galantes"