LONDON (AP) — Four centuries after the ‘Gunpowder Plot’ to blow up the Houses of Parliament and King James 1, descendants of the adversaries clasped hands in reconciliation earlier this week in London. Against a backdrop of old gunpowder barrels, the Duke of Northumberland, a descendant of the family of Thomas Percy, one of the conspirators with Guy Fawkes in the November 5, 1605 plot, shook hands with the Marquess of Salisbury, whose ancestor was Robert Cecil, chief minister to King James I.

The historic handshake took place in Parliament’s Westminster Hall, where members of the Gunpowder Plot were tried and convicted for the conspiracy which is still commemorated with bonfires and firework displays around Britain and elsewhere on November 5 each year.

The Duke of Northumberland said Percy, who was executed with Fawkes for his part in the plot, had always been considered the ‘black sheep’ of the family, but the ninth Earl, Percy’s cousin, spent 16 years in the Tower of London just for being “vaguely implicated”.

“The Marquess of Salisbury’s family were responsible for my family’s incarceration, but I don’t think you can hold a grudge for 400 years!” he said.

The Marquess described his family’s history as “a pleasure.”

“To me, the Gunpowder Plot marked the beginning of the dominance of Parliament as the ultimate authority in this country,” he said.

The Roman Catholic conspirators, led by Fawkes, were angered by the Protestant King James’s decision to rescind a decision to relax penal laws against their co-religionists.

They smuggled barrels of gunpowder into the cellars of Parliament, but were betrayed before they could ignite them and blow up Parliament, the king and his nobles.

The ceremony earlier this week in London marked the launch of a series of events around Britain to mark the plot’s 400-year anniversary.

Chris Pond, project director of Gunpowder Plot 400, said this week’s handshake is believed to be the first such act of reconciliation between the former adversaries.

“We thought it was such an important aspect of British history, and that of Parliament, that we had to mark it,” he said.

This week’s commemorations also include an exhibition at Shakespeare’s Globe Theatre and another at Westminster Hall, both in London. Events in London will culminate tomorrow in the premi|0xe8|re of a new play about the plot at historic Tower Hill.