Stephen Alford’s book — his third about this period — catalogs the ceaseless efforts of Elizabeth’s courtiers to protect the life of Queen Elizabeth and preserve her kingdom against the endless conspiracies mounted by her enemies. The Watchers is an impressively researched and annotated piece of scholarship which offers a new perspective on the Elizabethan age.

The book’s backdrop is the tumult Henry VIII created when he set aside his aging wife Catherine of Aragon, who was unable to produce a male heir to ensure the Tudor succession. Besotted with Anne Boleyn, Henry was confident the seductive Anne would do so. Unable to obtain an annulment from the pope, Henry renounced Rome and declared himself head of the Church of England. The resulting religious and political turmoil lasted for decades, roiling the short reign of Henry’s unfortunate son Edward VI and that of Catherine’s daughter, Mary I.

In 1558, the crown came to Henry’s last surviving child, Elizabeth, daughter of Anne Boleyn. Catholic Europe was aghast, believing that Elizabeth, a Protestant, was a heretic, a bastard and a usurper with no right to rule. Far from being a glorious period of peace and national unity, never during Elizabeth’s 45 years on the throne did the crown rest easily upon her head.

Fortunately for Elizabeth, she was served by brilliant and resourceful men led first by William Cecil, who grew old in the service of his queen; he was then followed by his son, Robert, who like a mandarin, was brought up for court service. Working with William Cecil, Sir Francis Walsingham developed and operated a sophisticated intelligence gathering operation directed largely at English Catholic expatriates in Europe, a number of who were indeed plotting endlessly against the queen.

William Cecil, Walsingham and the cast of agents they recruited, trained and launched tried to search out and vitiate plots and identify the plotters. The 16th-century intelligence service which resulted was remarkably modern; Alford’s mastery of the period and extensive use of original documents sets his readers right into the shadowy and contradictory world of espionage. The Watchers seems at times more likely to have sprung from the pen of John Le Carré than that of a Cambridge history don. Ciphers, disguises, “covers,” double agents, intercepted letters, gruesome executions, torture, bribed servants — all techniques common in modern espionage — were all employed by Elizabeth’s courtiers.

Mary, the Catholic Queen of Scots, foolishly sought refuge in England when deposed by the Presbyterians in 1567. Instantly she became a rallying point for Elizabeth’s enemies and just as quickly, Alford writes, she joined their conspiracies. Mary, the great granddaughter of Henry VII and widow of Francis II of France, believed her claim to the English crown superior to that of the heretic bastard Elizabeth, and was supported in this claim by her ambitious and powerful French relations.

Mary’s very presence in England personified one of the principal dilemmas of Elizabeth’s reign. Never willing to gamble that a husband might not seek her power for himself and believing that a designated heir would become the focus of conspiracies, Elizabeth engaged in endless flirtations but never married. To the utter despair of the fiercely loyal Cecil who served his queen with exemplary devotion, she refused to name an heir. In this vacuum, Mary’s impatient supporters, with the aid of powerful Catholics, urged that the crown should be Mary’s as soon as possible in order to return England to the Catholic fold and supplant the illegitimate and apostate “Jezebel” who had no right to rule.

By 1586, after Mary had been confined in England for 18 years, she was finally brought to trial for involvement in a plot. Relying on evidence painstakingly gathered, and in some instances created, by Walsingham’s operation, Mary was convicted of conspiracy to overthrow the queen. Elizabeth, vacillating, understood completely that her crown could never be secure while Mary lived but struggled mightily with the concept of regicide and the moral implications of sending her own cousin to the block. As soon as she finally signed the death warrant, her Privy Council dispatched it secretly to Mary’s executioners. Elizabeth was furious, even at her faithful Cecil, who, by forcing a conclusion to this great drama, removed the principal threat to his queen.

Mary’s execution did not, however, end the plots against Elizabeth. The Cecil/Walsingham operation was still necessary, and their efforts provided early warning of the Spanish Armada and exposed several additional plots against the queen. Philip II of Spain, who had been Elizabeth’s brother-in-law through his marriage to Mary I, was deeply involved in various plots against Elizabeth, including a brazen one in which her personal physician was to poison her.

Anglophiles as well as spy story aficionados will enjoy this exciting book and will appreciate Alford’s skill in requiring readers to consider whether, even when examined after four-and-a-half centuries, a worthy goal justifies dubious means.

Penny Farthing practices law in Washington. As an Anglophile as well as a bibliophile, she enjoys reading and reviewing books on English history.