Until recently, historians have argued that Mitchell was upset by the lack of interest shown by politicians in London about colonial affairs and so set out to warn them about the dangers posed to the British colonies by the French. Mitchell did so, on his own initiative, by making a first map of North America in 1750, which he then showed to the politicians he knew through his botanical and gardening activities. The map so impressed George Montagu-Dunk, 2nd Earl of Halifax, appointed president of the Board of Trade and Plantations in 1748, that Halifax opened up the official archives and solicited new maps from the colonies for Mitchell to make a new and better map. This was the map published in 1755. That is, the motive force for preparations against the French threat is understood to have come from a colonist who sought to take control of the colonies' future on behalf of the other colonists. (See, for example, the accounts by Ristow and Berkeley & Berkeley.)