These are the most valuable sources for the crusade of Frederic II. Each of the contestants tells the story from his own standpoint. We have comparatively little data for controlling their statements and determining their motives.
- Letters of the Sixth Crusade: Letter from Frederic II to Henry III of England in I229.
- Letters of the Sixth Crusade: Letter from Gerold, Patriarch of Jerusalem, to all the Faithful in 1229.
- Letter from the Master of the Hospitalers at Jerusalem to Lord de Melaye in I244.
- Letter from Guy, a crusader Knight, to B. of Chartres in I249.
- Letters of the Sixth Crusade: Letter from Frederic II to Henry III of England in I229.
- Letters of the Sixth Crusade: Letter from Gerold, Patriarch of Jerusalem, to all the Faithful in 1229.
- Letter from the Master of the Hospitalers at Jerusalem to Lord de Melaye in I244.
- Letter from Guy, a crusader Knight, to B. of Chartres in I249.