proof of its validity. But what if when the witnesses appear they say that they know  nothing of the charter, or answer doubtfully with respect thereto, and he who produces  the charter is suspected of having acquired it by fraud, because he was the  donor's chamberlain, or by the fraud of [the donor's] wife, or [if] there is some other  strong presumption against him? Neither the charter nor the gift will be valid, because  of the presumption, especially since it proves nothing.
A charter may be proved otherwise than by witnesses.
 A charter may also be proved otherwise than by witnesses and the country, by a comparison  of seals, as where, when a charter1 is disputed, other seals, which have once  been produced in court and approved and acknowledged by the donor, are compared;  if they agree completely and in all respects, so that no difference is discernible in  them, this alone suffices as proof of the charter and everything contained in it will be  held valid, unless something is found in the charter which arouses manifest suspicion,  as where an erasure has been made in a suspicious place, that is, in the statement of  fact, it is otherwise if in the statement of law.2 Rights may be written anywhere since  they are not varied or changed by erasure.3[A charter ought to appear in its original  form, without any flaw, erasure or cancellation,4 because it is not proper that a disputed  document have authority in court.]5 In writings some matters raise a slight  presumption, which may be overcome by the true proof of witnesses to the contrary  and by the country, as where a difference of pen is found, [that is], a difference in  writing and different hands, for one person writes in one way and another in another,  a young man in one and an old man in another, or6 of ink and pigment, as where in  one part it is written in black ink and in another in red.
A seal may be proved by comparison.
 When a seal ought to be proved by comparison and several sealed instruments made  in his name are put forward [by him] who has the onus of proof, reliance must not be  placed upon them, since they may all be forged, unless one of them was earlier produced  in court and acknowledged by the donor or proved genuine by the person  producing it,7 as where one first grants land to another for a term and at farm and an  instrument is made thereon