McCullough’s Roman a Clef : THE FIRST MAN IN ROME <i> By Colleen McCullough (William Morrow: $22.95; 914 pp</i> .<i> ) </i>

In at least one respect the parallel is discomfiting: a national political leadership in which great wealth is essential to achieve power. But it’s not Washington, D.C., 1990, where dug-in incumbents defy political unknowns with lean pocketbooks to unseat them. It is, instead, the city-state of Rome in 110 BC, and the republic that has endured for more than 300 years has become fat, corrupt and inept, and is beginning to unravel faster than a 39-cent pair of socks.

This is the critical juncture that novelist Colleen McCullough-- she, primarily, of the enormously popular “The Thorn Birds”--has chosen as the take-off point for her awesome and epic new work, “The First Man in Rome.” And, for her protagonist, she has wisely zeroed in on a most unusual man living in a most unusual time frame: Gaius Marius, tremendously gifted both militarily and organizationally and, alas, doomed in spite of his wealth to second-rate political status.

For it is not enough in this flaccid period of the Republic to have vote-buying and favor-granting wealth, alone. Inbred and obsessed with blood lineage, the path to the senate and, ultimately, to the post of consul , also requires an impeccable pedigree. Even though Marius, wealthy through land holdings and mining interests, has attained a seat in the senate through powerful friends, it is pretty well the end of the political line for a man sneeringly dismissed by his enemies as “an Italian hayseed with no Greek.”

This is a complex and critical period in Roman history. In the previous century, beginning in about 264 BC, the city-state has become the undisputed military and political leader of the civilized world. But its reach is exceeding its grasp and it is saddled with generals who can’t general and a citizenarmy (one must be a landholder to serve) that has become disillusioned and burned out. Politicians buy their way to the revolving post of consul only as a stepping stone to a post-consul appointment to the post of governor of a province that, at their leisure, they can then ravage and loot without restraint.

Fittingly, McCullough, in referring to Marius as “The First Man in Rome,” is labeling him, also, as Rome’s first “New Man”--a new breed rising to prominence in spite of his lineage and, in effect, opening up the era of one-man rule characterizing the Roman Empire that would follow on the heels of the republic. For Marius, though, nothing would have been possible without the intervention of the powerful Gaius Julius Caesar Nepos, father of the Julius Caesar whose name has become synonymous with the Roman Empire, and whose bloodline is flawless.

But flawless bloodline, or not, Caesar is not wealthy enough to assure both of his sons the gold needed to climb the political ladder and, at the same time, provide his two daughters with handsome dowries. It is the vital quid pro quo of Marius’ life--his wealth to assure Caesar the inheritance he needs, and in exchange, Caesar’s 18-year-old daughter, Julia, as Marius’ wife. (Never mind that the 48-year-old Marius has a wife of 20 years--divorce in Rome in 110 BC was a simple matter of the husband signing a parchment of divorcement.) It is, perhaps surprisingly, a most harmonious marriage in addition to giving Marius the entree he needs.

Firmly established as the consul, Marius quickly resolves the African revolt headed by Jugurtha, King of Numidia and becomes the instant darling of Rome to the point where he is reelected to the post of consul in absentia , which, at the time, was without precedent.

This six-time consul is a remarkable man, surrounded by other remarkable men--many of them venal, cowardly and self-seeking, but others, such as Lucius Cornelius Sulla, Marius’ chief aide in both the African and German campaigns, fully as complex and as talented as the consul himself.

Sulla is a brooding and curious man: Although with an untainted blood-line, he was as shut out of Roman political affairs by his poverty as Marius himself had been by his humble birth. Most of his early life has been spent on the low side of the social scale--debauchery and blatant misconduct with members of both sexes for openers. How Sulla resolves his shortcoming (the necessary wealth for ascendancy) is vastly different from Marius’ solution and up a far darker path. And yet, as different in temperament and morality as they are, these two men, both born leaders, fit together like a hand in a well-oiled glove.

Latin purists may quarrel with some of McCullough’s use of phrases that, admittedly, sometimes clang on the ear as anachronisms. We can accept that, in one form or another, Latin had words literally translating as “a pimp and a pansy”--not to mention any number of bodily functions--for instance, but some of the expletives in particular have more of the ring of the language heard in a 20th-Century truck stop than in a patrician household in Rome in 110 BC.

Let’s face it, too: “The First Man in Rome,” is, far and away, the story of the men who shaped Rome’s destiny in an age where women were chattel (bought, sold, traded, given away in marriage without question); most of the women emerge two-dimensionally. In all fairness, though, McCullough’s treatment of the women foremost in both the life of Marius (Julia, Gaius Julius Caesar Nepos’ eldest daughter) and of Sulla (Julilla, Julia’s younger sister) are fleshed out more richly. Julia is strong-willed; Julilla, knowing full well that there is something drastically wrong in her relationship with her husband, is weak and tragedy-prone--conditions that have no chronological boundaries.

This is an absolutely absorbing story--not simply of the military and political intrigues that went into the final days of the Republic but also of what it was like to live, love and survive at this pivotal point in our civilization. McCullough’s research is mind-boggling (the illustrations and maps are by her, too), but this is pretty dry stuff by itself. It takes a master storyteller to weave this sort of tapestry into a 900-plus-page novel that is every bit as hard to put down as it is to pick up.

Much has been made of the mastery of the novelist who can condense an unforgettable story into a few pages (Stephen Crane’s “The Red Badge of Courage” takes just 250 pages); too little has been said about the skill that goes into a sprawling story almost four times that length without the reader’s interest flagging at any point.

Nothing in life is free, though, and “The First Man in Rome” requires some concentration, and back-tracking, by the thoughtful reader. Geographic names, for instance, are confusing, and while McCullough’s plentiful maps are helpful, it is still touchy business; for instance, trying to relate Numidia Occidentis to our 20th-Century understanding of North Africa’s coastline.

Readers who delighted in the late Mary Renault’s novels built around ancient Greece will be equally enchanted by “The First Man in Rome,” and by McCullough’s promise that it is but one of several she plans on the waning days of the Roman Republic and the birth of the Empire. No less delightful, too, is the author’s 123-page glossary with absolutely fascinating trivia in it: The Roman toga measured 15 feet wide and more than 7 feet long and made the wearing of underwear, and certain biological functions, logistic impossibilities.