Martin McGuinness is a peacemaker who wants to bring unionists and nationalists together, a leading Protestant clergyman has said.
Rev David Latimer, a Presbyterian Minister from Londonderry who has formed a friendship with the top republican, attended his meeting with the Queen.
The clergyman, who famously addressed the Sinn Fein annual conference last year where he also praised Mr McGuinness's contribution to the peace process, said the royal handshake was historic.
He added: "Let me tell you this, and tell you it with all my heart, Martin McGuinness is a peacemaker.
"He is wanting to shape things so that both communities will be able to move closer together, to become friendly allies and never again need to think of becoming warring adversaries."
He challenged critics who accuse Sinn Fein of using the meeting with the Queen for political ends.
"I wonder how well cynics who want to dilute the significance of today really know Martin McGuinness," the churchman said.
"I know him over a six year period and I've got to tell you that guy, if he's doing something, he's doing it because he believes in it. And I trust that man totally, because we built up that kind of relationship."
Rev Latimer welcomed the handshake between the former IRA leader and the monarch.
"Today is a moment in history that I think that people will look back to, and they will see that something happened to send out a message to everybody that this peace process is not a dream we're living in."