Two Slices of Historical Romance

THE PALACE OF WISDOM, By Bob Marshall-Andrews. New York: E. P. Dutton. 341 pp., $18.95. SOME periods of history inspire historians and novelists alike - they write volume after volume.

Library shelves creak and warp under the weight of the many books written about Florence during the artistic and mercantile boom known as the Renaissance, about the Medici family, the uncrowned rulers of Renaissance Florence and patrons of Botticelli, Michelangelo, and Raphael.

But books about post-Renaissance Florence? Or Cosimo de Medici III, Grand Duke of Tuscany? Nothing.

Bob Marshall-Andrews's entertaining new novel, ``The Palace of Wisdom,'' takes readers into this unmapped and unfamiliar historical territory of late 17th-century Florence. Written as a memoir, ``The Palace of Wisdom'' relates the story of Fredo Credi, linguist and scholar of international repute, his childhood in the Tuscan countryside, and his tumultuous 15th year when he served as apprentice to Antonio Magliabechi, head librarian of the private Medici library.

If that sounds as dreary as a book of 19th-century sermons, don't be misled. ``The Palace of Wisdom'' is a boisterous, bawdy tale of espionage and derring-do, of brain versus brawn, and buffoonery.

The only child of a minor intellectual and book collector, barrel-shaped Credi spends his childhood translating the classics, devouring the latest scientific or philosophic texts, and eavesdropping on his parents and their friends. This idyllic existence is marred only by the occasional bullying of Pasto Bamboni, son of the local butcher, reknowned for his oxlike strength, piggy eyes, and swinish behavior.

Meanwhile, Florentine affairs have reached a state of corrupt chaos. Hypochondriacal Cosimo III is increasingly swayed by his mother. Together, they reintroduce the Inquisition to Florence. Upon his parents' murders, in which Pasto Bomboni is implicated, Credi joins forces with Magliabechi against despotic censorship, book-burning, and the violent anti-Semitism of the Medici and the Inquisition.

Marshall-Andrews writes unflinchingly about the quality of life in 17th-century Italy. His is not the romantic roseate view of such historical novelists as Baroness d'Orczy. Instead, he walks us through garbage-filled streets, nostrils flaring with the stench from the Arno River, allows us to eavesdrop on the coarse conversations of the Medici's secret police, and shows us the quack medical remedies of the day.

But Marshall-Andrews never loses his sense of historical good humor. His work is refreshingly candid and probably as close to realistic as the distance of three centuries allows. He creates a cast of characters both colorful and flamboyant - an unlikely assortment of geniuses and rogues, including dwarfs, Turks, and a defrocked Irish friar.

The librarian is a man devoted to learning and justice, a compassionate man, but crippled and ugly. The narrator is an all-too-human combination of braggadocio, brilliance, and sartorial bad taste, with a strong leaning toward bombast which adds to, rather than detracts from, his appeal.

The novel opens with a quote from William Blake: ``The road of excess leads to the palace of wisdom.'' It then demonstrates why this is good counsel. Beneath the disarmingly rollicking surface of ``The Palace of Wisdom'' lie some essential truths about the nature of racial bigotry, censorship, and the abuse of power. Marshall-Andrews offers a remarkable combination: an intellectual banquet with belly laughs for dessert.