Robert Catesby, a man of "ancient, historic and distinguished lineage", is the inspiration behind what will come to be called the Gunpowder Plot.

Described by contemporaries as "a good-looking man, about six feet tall, athletic and a good swordsman", he along with several other conspirators, had taken part in the Earl of Essex's rebellion in 1601, during which he was wounded and captured.

Queen Elizabeth had allowed him to escape with his life after fining him four thousand marks (equivalent to over six million pounds as of 2008), to afford which he had been forced to sell his estate in Chastleton.

Catesby in 1603 had helped to organize a mission to the new King of Spain, Philip III, urging Philip to launch an invasion attempt on England, which they assured him would be well supported, particularly by the English Catholics.

Thomas Wintour had been chosen as the emissary for the mission to Spain, but the Spanish king, although sympathetic to the plight of Catholics in England, had been intent on making peace with James I.

Wintour had also attempted to persuade the Spanish envoy Don Juan de Tassis that "three thousand Catholics" were ready and waiting to support such an invasion.

Pope Clement VIII had voiced his concern that using violence to achieve a restoration of Catholic power in England would result in the destruction of those that remained.

According to contemporary accounts, in February 1604 Catesby had invited Wintour to his house in Lambeth, where they had discussed Catesby's plan to reestablish Catholicism in England by blowing up the House of Lords during the State Opening of Parliament.

Wintour is known as a competent scholar, able to speak several languages, and he had fought with the English army in the Netherlands.

His uncle, Francis Ingleby, had been executed in 1586 for being a Catholic priest, and Wintour had later converted to Catholicism.

Also present at the meeting was John Wright, a devout Catholic said to be one of the best swordsmen of his day, and a man who had taken part with Catesby in the Earl of Essex's rebellion three years earlier.

Despite his reservations over the possible repercussions should the attempt fail, Wintour had agreed to join the conspiracy, perhaps persuaded by Catesby's rhetoric: "Let us give the attempt and where it faileth, pass no further."

Wintour had traveled to Flanders to inquire about Spanish support.

While there he sought out Guy Fawkes, a devout Catholic who had served as a soldier in the Southern Netherlands under the command of William Stanley, and who in 1603 had been recommended for a captaincy.

Accompanied by Christopher Wright, Fawkes had also been a member of the 1603 delegation to the Spanish court pleading for an invasion of England.

Wintour has told Fawkes that "some good frends of his wished his company in Ingland", and that certain gentlemen "were uppon a resolution to doe some whatt in Ingland if the pece with Spain healped us nott".

The two men late in April 1604 return to England, telling Catesby that Spanish support is unlikely.