Any person interested may appear and defend against the probating of a will. The principal defenses which may be made (outside of those relating to the formal execution of the instrument) are mistake, fraud, and undue influence.

"An instrument executed as a will under a mistake as to its identity cannot be probated by reason of lack of animus testandi." Thus, where two wills were prepared, one for each of two sisters, and each by mistake executed the instrument prepared for the other, neither was entitled to probate.3 A will executed in consequence of some collateral mistake, such as the supposed death of a relative, stands on a different footing. Here the testamentary intention exists, although the form in which it manifests itself may be materially affected by the mistake. But this fact will not affect the validity of the will.4 Statutory changes in the law on this point have occasionally been made."

1 Definition from American & Eng. Ency. of Law, Vol. XXII, page 111.

2 See Statutes of the Several States.

3 Goods of Hunt. 3 P. & D.. 250.

The influence of fraud upon a will is thus discussed in the case of Kennell vs. Abbott.5

"The cause arises upon the will of Catherine Hickman, who supposed herself to be married to Edward Lovell; with whom she had celebrated a marriage. It now appears that he was a married man at that time; therefore, she is in fact a single woman; and it was a gross fraud as to her. She made her will in execution of the power given to her by the articles executed previously to the supposed marriage; and not aware that she was a single woman. Upon that will the questions arise. The first question is, whether this legacy of $1.50 charged upon the produce of the sale of the copyhold estate devised in trust to be sold is or is not a legacy which this man can claim under the circumstances that it is given to him as the husband of the testatrix; though he does not possess that character. I thought it a case rather novel in its circumstances, and that scarcely has afforded any decision in the law of England; though there are some dicta in the civil law, that seem to bear upon this point. The passage cited from the Code, I think, does not much apply. The passage in the Digest is: 'Falsam causam legato non obesse verius est, quia ratio legandi legato non cohaeret; sed plerumque doli exceptio locum habebit, si probetur alias legaturus non fuisse.'

"The meaning is, that a false reason given for the legacy is not of itself sufficient to destroy it, but there must be an exception of any fraud practiced, from which it may be presumed; the person giving the legacy would not, if that fraud had been known to him, have given it. That from a book of great authority seems to be the principle of the civil law.

4 Maynard vs. Tyler, 168 Mass., 107: 41 N. E., 413.

5 4Ves., 802.

'The question is, whether according to the law of England, that can apply to a case like the present; and whether the law will permit a man, who obtains a legacy in such a manner, to have the benefit of it. I have not been able to find anything that bears any very decisive analogy to this; but upon general prin-siples, I am of opinion, it would be a violation of every rule that ought to prevail as to the intention of a deceased person, if I should permit a man availing himself of that character of husband of the testatrix, and to whom in that character a legacy is given, to take any part of the estate of a person whom he so grossly abused; and who must be taken to have acted upon the duty imposed upon her in that relative character. I desire to be understood not to determine that, where from circumstances not moving from the legatee himself, the description is inapplicable, as where a person is supposed to be a child of the testator, and from motives of love and affection to that child, supposing it his own, he has given a legacy to it, and it afterwards turns out that he was imposed upon, and the child was not his own, I am not disposed by any means to determine that the provision for that child should totally fail; for circumstances of personal affection to the child might mix with it; and which might entitle him, though he might not fill that character in which the legacy is given. My decision, therefore, totally avoids such a point. Neither would I have it understood, that if a testator in consequence of supposed affectionate conduct of his wife, being deceived by her, gives her a legacy, as to his chaste wife, evidence of her violation of her marriage vow could be given against that. It would open too wide a field. But this decision steers clear of that point. This is a legacy to her supposed husband and under that name. He was the husband of another person. He had certainly done this lady the grossest injury a man can do to a woman; and I am now called upon to determine, whether the law of England will permit this legacy to be claimed by him. Under these circumstances I am warranted to make a precedent and to determine, that wherever a legacy is given to a person under a particular character, which he has falsely assumed, and which alone can be supposed the motive of the bounty, the law will not permit him to avail himself of it; and, therefore, he cannot demand his legacy.

"A case (Ex parte Wallop 4 Bro., C. C. 90), something like this occurred lately; which took up so much time before the Lords Commissioners upon an application for a writ de ventre inspiciendo against a woman, who had lived with Mr. Fellows, and had made him believe she had been brought to bed of several children; which he was weak enough to suppose were his. It was not a question whether they were his children, for if so, I do not apprehend the decree would have been such as it was. But there were no such children. She had shown him children as hers, which were not hers; and he gave legacies to them, as her children by him. It was held, that they were not entitled. There two things were wanting. The testator was not merely deceived as to their being his children; but he was deceived as to the other ingredient of the character in which he gave them the legacies; for they were not the children of that woman. Therefore, upon the principle I have mentioned from the Digest, and that ought to govern the courts of justice, I am of opinion this legacy could not be claimed."

Undue influence consists of means employed to overcome the free will of the testator, which, under the existing circumstances, he could not well resist. In order to render a will invalid, the free will of the testator must have been overcome to such a degree that the will cannot be considered as expressing his true wishes and intention.6

6 Hall vs. Hall, L. R. I. P. & D., (48).