The sole issue on appeal is whether a deed dated December 15, 1970, signed by the husband and wife and conveying to the wife alone the real estate originally held by the parties as tenants by the entirety was “duly acknowledged” as required by G. L. c. 209, § 3, as in effect prior to St. 1975, c. 558, § 2,1 where the deed was *861acknowledged only by the wife. The judge dismissed the husband’s complaint brought on March 19, 1975, to set aside the conveyance, ruling that the wife’s acknowledgment was sufficient to validate the deed. On the wife’s counterclaim for declaratory relief, the judge declared the deed valid and binding between the parties and effective to convey title to the wife. We agree with the judge’s ruling, for the reasons stated below.

The facts are not in dispute. On June 25, 1969, the Gordons acquired the land in question as tenants by the entirety. Their relationship before and after the purchase of the property was marked by marital discord. Toward the end of 1970 they had resumed a joint marital domicil in Boston and were in the process of trying to improve their relationship. On December 14, 1970, following a conversation between the spouses on the preceding day, Mrs. Gordon went to an attorney and told him, “Harry wants the deed changed into my name.” On December 15,1970, Mrs. Gordon picked up a deed prepared by the attorney, dated December 15, 1970, with the names of both spouses typed on the acknowledgment portion of the deed. That evening, in the bedroom of their home, Mr. Gordon signed the deed.2 Mrs. Gordon signed it on the morning of December 16,1970, and took it, by herself, to a notary public before whom she acknowledged the instrument to be the free act and deed of herself and of her husband. Mr. Gordon was not present at that time. The notary affixed his signature and seal below the recitation that both had personally appeared *862before him and acknowledged the instrument as their free act and deed.3 Mrs. Gordon then took the deed to the attorney with instructions to have it recorded. For some unexplained reason, the deed was not recorded until July 6,1971. On October 11,1974, Mrs. Gordon commenced a divorce action which subsequently resulted in a final judgment of divorce.

The issue before us is whether the wife’s acknowledgment is sufficient to validate the deed under G. L. c. 209, § 3.4 That statute, as in effect prior to St. 1975, c. 558, § 2, expressed a legislative decision to allow transfers of real property between husband and wife, and to impose upon such transfers the requirement that a deed between husband and wife be “duly acknowledged and recorded ... .”5 The principal function of an acknowledgment is that it is required for the recording of a deed, and furnishes formal proof of the authenticity of the execution of the instrument when presented for recording. See McQuatt v. McQuatt, 320 Mass. 410, 413-414 (1946). In ordinary circumstances, title to real estate may be trans*863ferred by a deed which has not been acknowledged, and such deed is good against the grantor and his heirs and those having actual notice. G. L. c. 183, § 4, as appearing in St. 1941, c. 85. By G. L. c. 209, § 3, however, the acknowledgment and recording of a deed between husband and wife was made a statutory prerequisite and is necessary to the validity of the deed. The purpose of the provision requiring acknowledgment and recording, as expressed by the court in Malaguti v. Rosen, 262 Mass. 555, 564 (1928), “was to. prevent the deception and defrauding of creditors by making gifts of real property ineffective unless evidenced by recorded deed.”

General Laws c. 209, § 3, does not specify by what method a deed between spouses is to be “duly acknowledged.” For aid in construction we turn to G. L. c. 183, § 30, which provides that the “acknowledgment of a deed ... shall be by one or more of the grantors or by the attorney executing it.” A “grantor” is defined in G. L. c. 4, § 7, Eleventh, as “every person from or by whom a freehold estate or interest passes in or by any deed ... .”6 In Hayden v. Peirce, 165 Mass. 359 (1896), the court held that a husband alone can acknowledge a deed of his wife’s separate property where his interest is only an estate by curtesy and he is a “grantor” only in the sense that he is releasing his curtesy rights. Accord, Palmer v. Paine, 9 Gray 56 (1857); Perkins v. Richardson, 11 Allen 538 (1866).7 In Shaw v. Poor, 6 Pick. 86, 87-88 (1827), the court held that, under a predecessor statute to c. 183, § 30, acknowledgment of a deed by one grantor was suf*864ficient, even though the deed was not acknowledged by the other grantor, who was solely seized of that part of the property at issue.

We think that the liberal judicial construction given to the word “grantor” as it now appears in G. L. c. 183, § 30, should be applied in the present case. The husband contends that the only interest that could be conveyed by the deed is the freehold interest of the husband, and that he alone is the grantor of that interest. We take this argument to mean that it is the husband alone who is relinquishing interest in the property and thus is the only true “grantor.” However, we agree with the judge’s ruling that, when a husband and wife holding lands as tenants by the entirety convey such property, both husband and wife are grantors, not the husband alone. The nature of the tenancy by the entirety is such that, as defined at common law, both husband and wife have one and the same interest. See 4A Powell, Real Property par. 620 (Rohan ed. 1978).8 The spouses hold one indivisible estate in them both and in the survivor, this concept being founded ón the common law doctrine that, in law, husband and wife constitute but one person. See Bernatavicius v. Bernatavicius, 259 Mass. 486, 487 (1927). With regard to the present case, we need not rely directly on this rather abstruse concept of a fictitious unity of persons,9 in view of the foregoing judicial interpretations of the word “grantor” in c. 183, § 30. We conclude that either spouse alone could acknowledge the deed in question, since both at the time of conveyance had a freehold interest in the property, both joined in executing and signing the deed, and both spouses, therefore, were grantors within the meaning of G. L. c. 4, § 7, Eleventh.

*865The husband argues that the wife cannot be a grantor because she is also the grantee of the deed, and one cannot convey by deed to oneself. While it is true that a person cannot convey to himself alone10 (Park, Conveyancing, supra § 57), that is not the case here, where the freehold interest which was held by both the husband and wife was transferred to the wife.

Since the wife was one of the grantors to the deed, her acknowledgment alone satisfies the requirements of c. 183, § 30, making the deed “duly acknowledged” pursuant to c. 209, § 3, and effective to pass title to her.

Judgment affirmed.