Probate, in law, the proof, before the competent authority, that an instrument offered purporting to be the last will and testament of a person deceased is indeed his lawful act. Until the act 20 and 21 Victoria, c. 77 (1857), amended the law relating to probates and letters of administration in England, the custody of the estates of all deceased persons vested there primarily in the ordinaries or bishops of dioceses, subject only to the exceptional rights of the crown or of lords in respect to certain manors. The new act of 1857 abolished the ancient ecclesiastical jurisdiction, and conferred full and exclusive authority over all testamentary causes upon the queen, to be exercised in her name in a court to be called the court of probate. Ecclesiastical courts never existed in the United States; but from the very settlement of the country the office and functions of the English ordinaries have been exercised here by similar officers under various titles, such as surrogate, register of wills, judge of probate, and ordinary, and generally with larger powers than those functionaries possessed. In some states the county courts, and in others the orphans' courts, grant letters of probate.

These several judicatures have different powers, some only concerning themselves with the factum of a will, leaving its construction, or the operation and effect of its particular provisions, to the courts of law; but others are vested with complete jurisdiction of all matters pertaining to the administration, subject to appeal to some higher court. In England the rule has been that probate was necessary of such instruments only as were testamentary and regarded personal property. If they affected lands alone they needed not to be proved in the spiritual courts. In this country the general rule by statute is that no will is effectual to pass either real or personal estate unless it has been duly proved and allowed in the probate court; and so long as the probate remains unreversed on appeal, the due execution of the will, the sanity or capacity of the testator, and the attestation of the witnesses, cannot be called in question in the courts of common law. The same rule is in some states observed in respect to wills once admitted to probate, though they were made and executed in other states according to forms not sufficient where they were approved.

In some states the probate of wills of lands is prima facie evidence, but not conclusive, of the due execution of these instruments; in others the probate becomes conclusive in these respects after the lapse of a certain number of years. - In most of the states the procedure of the court upon probate is fixed by the legislature, and the common law distinction between probate in common form and in solemn form has in great measure disappeared. A will is said to be proved in common form when the executor presents it to the court, and, without summoning any of the parties interested, calls one or more witnesses to prove its execution. The objection to this mode of proof was, at common law, that at any time within 30 years the executor might be called upon by any party in interest to make proof in solemn form. Proof is made in solemn form, or by form of law or per testes, when all persons whose interests are to be affected by the will have been duly notified to be present, and have had opportunity to be heard in the premises. This is now the usual mode of proof in the United States, and after the will is approved in this way it is for ever binding. The method of proof, however, like many other points of probate practice, is often regulated by particular statute provisions.

The testimony which the judge calls for at the hearing relates to the factum of the will, as the phrase is. The question being whether the instrument is a will or not, it is of the first importance to inquire into the capacity of the testator, and whether he did in fact execute the alleged will as it purports to have been executed. It is to furnish evidence on both these points that disinterested persons are invited to witness the execution of a will. These attesting witnesses are then most essential parties in a question of probate. Generally all of them must be summoned if they are living within the process of the court; but if from death or absence from the country, or from incompetency arising since the attestation, any witness cannot be produced, the will may be proved by the others and by proof of the handwriting of the party who fails. If all are dead, or out of the court's jurisdiction, the handwriting of all must be proved; and probably in such a case the handwriting of the testator also. The attestation clause is generally framed with a regard to the requirements which the statutes of the state where it is made render essential to the valid execution of a will.

If the evidence of the witnesses shows plainly that these requirements were not followed, the presumption of a valid execution furnished by the recital of them is overset; but if the subscribing witnesses have lost all recollection of the particulars of the transaction, the formal execution will generally be presumed and the will admitted to probate. Failure of memory on the part of one of the witnesses may often be supplied by the evidence of another or of the rest of them. In affixing his name, an attesting witness is regarded as certifying the capacity of the testator. His subsequent attempt to impeach the instrument by declaring that the testator did not execute the will with an intelligent and disposing mind is justly open to suspicion. Evidence of this character is not to be entirely rejected, though it avails little without the support of other testimony. When 30 years have passed since the death of the testator, a will is said to prove itself; the subscribing witnesses being presumed dead, the bare production of the instrument suffices.

The will must however have come from a custody which forbids question of its genuineness, and be in other respects free from suspicion, or the genuineness must in some way be proved. - Wills alleged to have been lost, destroyed, or mislaid, may be admitted to probate on proof of these facts, and on clear and satisfactory evidence of their contents. For a noted instance of this, see Gaines, Myra clark.