Mort Künstler, whose meticulously researched and dramatically composed paintings of American historical scenes, especially of the Civil War, made him one of the country’s most prominent historical artists, died on Sunday in Rockville Centre, N.Y., on Long Island. He was 97.

His daughter Jane Künstler said he died in hospice.

Mr. Künstler developed a sense of dramatic realism early in the 1950s as an illustrator for pulp novels and men’s adventure magazines. He refined his mainstream commercial appeal working for top ad agencies and magazines like National Geographic, where he learned the importance of conducting extensive historical research before ever dipping a brush in paint.

As he branched out in the 1970s to create large canvases of epic scenes in American history, including more than 350 images of the Civil War, he consulted historians and experts and visited the locations of his scenes to ensure the accuracy of his work.

His paintings sometimes challenged and corrected the factual details of well-known historical paintings, including one of the most famous: Emanuel Leutze’s dramatic 1851 rendering of “Washington Crossing the Delaware.”

In the Leutze painting, Washington, at daybreak, stands tall in a crowded rowboat beside an American flag, which hadn’t yet been adopted in 1776, when the crossing took place. Mr. Künstler, by contrast, after months of research, painted Washington in the dead of night gripping the wheel of a cannon on a 60-foot-long flatboat ferry guided by cable and crowded with dozens of troops and horses.