Two rulers hug in “Jahangir Embracing Shah Abbas,” which was painted around 1618. Curator Debra Diamond says the men were, in fact, rivals, which helps explain why this Mughal painting makes Jahangir appear larger and more splendid than the shah.

The illustrated books made in Persia and Mughal-ruled India between 1400 and 1700 are “among the greatest manu-scripts ever produced anywhere,” according to Debra Diamond, an organizer of the Sackler Gallery’s “Worlds Within Worlds: Imperial Paintings from India and Iran.”

Persian and Mughal manuscripts are also, she says, “deeply intertwined.” Yet they’re rarely shown together — even at the Freer and Sackler galleries, which together hold one of the world’s largest collections of the lavish artwork.

“Worlds Within Worlds,” which runs until Sept. 16 at the Sackler, reveals the continuity among books handmade for the rulers of both countries. The illustrations show historical events, scenes from sacred texts — Muslim, Hindu and even Christian — and the grandiose dreams of Emperor Jahangir, who reigned from 1605 to 1627 as part of the Persian-rooted Mughal dynasty that ruled northern India.

The show displays a wealth of paintings, calligraphy and exquisite bindings. Yet it contains only about 20 percent of the Freer and Sackler’s holdings in this area, says Massumeh Farhad, the museums’ curator of Islamic art.

The show’s earliest items originated mostly in the city of Herat, which is now in Afghanistan. That region hasn’t received much good press over the past few centuries. But at the time these manuscripts were made, “Herat was the Paris of the East,” Farhad says.

The Persian style “showed an idealized world that was almost a fantasy land,” she says. Its images were flat and its faces flawless, rendered with gem-based opaque watercolors and plenty of gold leaf to create art that was literally opulent.

Working in Delhi, Mughal artists used the same essential techniques. But they incorporated bolder colors, realistic portraits and European-style perspectives. According to Diamond, who is also the museums’ associate curator of South and Southeast Asian art, the earliest Mughal paintings show “the beginning of the creation of a composite culture.”

Arthur M. Sackler Gallery, 1050 Independence Ave. SW; through Sept. 16, free; 202-633-4880. (Smithsonian)