Forced into hiding in the small clandestine retreats in the great Catholic houses, the Jesuit priests sent directly by the Pope to succour his oppressed flock became hunted martyrs across the landscape of Tudor and Stuart England.

The most ruthless of their pursuers was Sir Francis Walsingham, who established a spy network that would have been the envy of Britain's Secret Service.

Fresh from his recounting of the horrific last days of Henry III, Robert Hutchinson reveals in Elizabeth's Spy Master (Weidenfeld & Nicolson, £20) that at its peak his extensive espionage realm embraced 53 spies and 18 agents in foreign courts as well as a host of informers in England itself.

He brought many "from the highest born to the most lowly" to the scaffold and poisonously schemed to provide evidence for the execution of Mary, Queen of Scots, dressed in a blood-red satin petticoat that shocked even the witnesses of her death.

Walsingham was a man to fear. As Hutchinson shows in his panoramic portrait of the Elzabethan age, he was directly responsible for the defence of his queen by any means at his command.

He used a myriad of devices to protect her secret writing and code-breaking, bribery, extortion, blackmail and torture. The punishment for treason was the block or the gibbet, often with the refinement of drawing and quartering, liberally in use during the rule of her successor James I as the Gunpowder Plot unfolded.

The fate of many Jesuit priests is also the focus of Alice Hogge's God's Secret Agents (HarperCollins, £8.99), a gruelling chronicle of those in captivity and the stoicism with which the missionaries defied examination.

Hogge's theme could have been made much darker, but the poetic force she brings to it makes this book of very special value in the study of Catholic courage.