The phrase "a principal theme of" is correct and usable in written English.
It can be used when discussing the main idea or central topic of a piece of literature, art, or any other form of expression.
Example: "In her novel, the author explores a principal theme of love and sacrifice."
Alternatives: "a central theme of" or "a key theme of".
A principal theme of medieval pornography was the sexual depravity (and hypocrisy) of monks and other clerics.
The inquiry is an issue in the Philippine elections, where corruption is a principal theme of the opposition campaign against Mr. Marcos.
Boullée's emphasis on the psychology of the viewer is a principal theme of his Architecture, essai sur l'art, not published until the 20th century.
The "appliance of science" will be a principal theme of the strategy for manufacturing that the DTI is now drawing up.
The text is unfortunately lost, but a principal theme of the piece was probably the debate that had been going on since the 15th century over whether painting or sculpture was the greater visual art.
But some voters did pay attention to the issues, like Joshua Carlston, 29, a North Brunswick accountant who was focused on national security, a principal theme of Mr. Forrester's.
A principal theme is the attraction and repulsion of the anatomical focus of femininity to the male eye, which induces a fascinated fear, rather like standing on the edge of cliff.
Fugue, in music, a compositional procedure characterized by the systematic imitation of a principal theme (called the subject) in simultaneously sounding melodic lines (counterpoint).
His first-hand knowledge of the countryside's "beautiful green solitude" provided a principal theme, one illuminated in the peasant patois of 19th-century Northamptonshire, where a snail was a "pooty".
That's a principal theme in the most surprising movie hit of the year so far, "Get Out," whose box office haul in America crossed the $100 million mark last weekend.
The design and support of the central dome or cupola, together with the number and disposition of the subsidiary cupolas, remained for a long time the principal theme of Russian architecture.
