k of transport, and the condition of
the markets had all to be kept in mind when a fair price was being
fixed.[3] We may mention in passing that the power of fixing the just
price might be delegated; prices were frequently fixed by the town
authorities, the guilds, and the Church.[4]

[Footnote 1: Roscher, _Geschichte_, p. 19.]

[Footnote 2: _Op. cit._, IV. xv. 10.]

[Footnote 3: _Studien_, vol. ii. p. 43.]

[Footnote 4: Endemann, _Studien_, vol. i. p. 40; Roscher, _Political
Economy_, s. 114.]

The passage from Gerson which we quoted above shows that, when a just
price had been fixed by the competent authority, the parties to
a contract were bound to keep to it. In other words, the _pretium
legitimum_ was _ipso facto_ the _justum pretium_. On this point there
is complete agreement among the writers of the period. Caepolla says,
'When the price is fixed by law or statute, that is the just price,
and nobody can receive anything, however small, in excess of it,
because the law must be observed';[1] and Biel, 'When a price has been
fixed, the contracting parties have sufficient certainty about the
equality of value and the justice of the price.'[2] Cossa draws
attention to the necessity of the fixed price corresponding with
the real price in order that it should maintain its validity. 'The
schoolmen talk of the legitimate and irreducible price of a thing
which was fixed by authority, and was for obvious reasons of special
importance in the case of the necessaries of life.... The legitimate
price of a thing as fixed by authority had to be based upon the
natural price, and therefore lost its validity and became a dead
letter the moment any change of circumstances made it unfair.'[3]

[Footnote 1: _De Contractibus Simulatis_, 69.]

[Footnote 2: _Op. cit._, IV. xv. 10.]

[Footnote 3: _Op. cit._, p. 143.]

Sec. 3. _The Just Price when Price not fixed by Law_.

When the just price was not fixed by any outside authority, the buyer
and seller had to arrive at it themselves. The problem before them was
to equalise their respective burdens, so that there would be equality
of burden between them, or, in other words, to reduce the value of the
article sold to terms of money. In order that we may understand how
this equality was arrived at, it is important to know the factors
which were held to enter into the determination of value.

The first thing upon which the mediaeval teachers insist is that value
is not determi