To prove forgery of a will, conclusive evidence is required that the signature on the testamentary document is not that of the testator; expert evidence pointing to mere inconsistencies in signatures is insufficient where standard samples also show variation and where factors such as the testator's age, health, and the passage of time are not adequately considered. To establish undue influence in testamentary matters, it must be proven that the influence caused the execution of a document that does not truly express the testator's mind; the following factors must be considered: presence or absence of independent advice, unexplained unnatural changes to the will, secrecy and haste, and the testator's susceptibility to influence. Where a testator is of sound mind, approaches legal advisors independently, explains reasons for changes to a will, and is not isolated from other family members, undue influence cannot be established on the basis of speculation about relationships or mere benefit to a particular beneficiary.