“As the corporation's size and power grew, so did the need to assuage people's fears of it. The corporation suffered its first full-blown legitimacy crisis in the wake of the early-twentieth-century merger movement, when, for the first time, many Americans realized that corporations, now turned behemoths, threatened to overwhelm their social institutions and governments.”

Source: Fast Food Nation: The Dark Side of the All-American Meal

Source: Taking the Risk Out of Democracy: Corporate Propaganda versus Freedom and Liberty (1995), p. 18

Source: 1930s- 1950s, The Future of Industrial Man (1942), p. 96

This quote spread rapidly in the United States after appearing in a column by Molly Ivins (24 November 2002). It is repeated often and sometimes attributed to the "Fascism" entry in the 1932 Enciclopedia Italiana. However hard copies of the 1932 Enciclopedia Italiana exist in numerous libraries and the alleged quote is not in the text, nor is there anything that would support the alleged quote. A vaguely similar statement does appear in Doctrine of Fascism.
We are, in other words, a state which controls all forces acting in nature. We control political forces, we control moral forces, we control economic forces, therefore we are a full-blown Corporative state.
The same document explains that the "corporations" (corporazioni) on which the Fascist state rested were its own creations, modeled on guild associations and not private companies, which Italian normally calls società. For details see "Mussolini on the Corporate State" http://www.publiceye.org/fascist/corporatism.html by Chip Berlet.
Attributed

De Luce seu de Inchoatione Formarum (c. 1215-1220)
Context: The first corporeal form, which some call corporeity, I hold to be light. For light of its own nature diffuses itself in all directions, so that from a point of light a sphere of light of any size may be instantly generated, provided an opaque body does not get in the way. Corporeity is what necessarily follows the extension of matter in three dimensions, since each of these, that is corporeity and matter, is a substance simple in itself and lacking all dimensions. But simple form in itself and in dimension lacking matter and dimension, it was impossible for it to become extended in every direction except by multiplying itself and suddenly diffusing itself in every direction and in its diffusion extending matter; since it is not possible for form to do without matter because it is not separable, nor can matter itself be purged of form. And, in fact, it is light, I suggest, of which this operation is part of the nature, namely, to multiply itself and instantaneously diffuse itself in every direction. Therefore, whatever it is that produces this operation is either light itself or something that produces this operation in so far as it participates in light, which produces it by its own nature. Corporeity is therefore either this light, or is what produces the operation in question and produces dimensions in matter in so far as it participates in this light itself and acts by virtue of this same light. But for the first form to produce dimensions in matter by virtue of a subsequent form is impossible. Therefore light is not the form succeeding this corporeity, but is this corporeity itself.

Interview by Bill Moyers, Bill Moyers Journal, 30 April 2010 ( transcript http://www.pbs.org/moyers/journal/04302010/transcript2.html, video http://www.pbs.org/moyers/journal/04302010/watch2.html)

Source: The Corporation: The Pathological Pursuit of Profit and Power (2004), Chapter 6, Reckoning, p. 139

Dissenting, Citizens United v. Federal Election Commission, 558 U.S. ___ (2010).

Source: 1960s, Understanding Media (1964), p. 133