concurring:
I join in the majority’s opinion because I understand it to be in accord with the following comments.
In this case we hold no more than that in a prosecution for incest it is usually “competent for the commonwealth to introduce evidence of illicit relations between the parties prior to the commission of the specific offense laid in the indictment.” Commonwealth v. Bell, 166 Pa. 405, 411, 31 A. 123, 123 (1895).
In a prosecution for incest, evidence of the defendant’s prior lust for the complaining witness is relevant to show that the defendant was possessed with the same lust at the time of the incident. See Wigmore on Evidence § 360 (3d ed. 1940). The relevancy of such evidence is premised on the following three-step analysis. First, evidence that a defend*320ant sexually desired the complaining witness at the time of the incident is relevant as tending to show that the defendant acted to realize this desire. Second, evidence that the defendant sexually desired the complaining witness prior to the time of the incident is relevant as tending to show that the defendant possessed the same sexual desire at the time of the incident. Third, evidence of sexual relations between the defendant and the complaining witness shows that the defendant sexually desired the complaining witness at the time those relations occurred. See Wigmore, supra §§ 117, 399, 400.
This reasoning is unexceptionable. It is analogous to the reasoning used in a prosecution for assault, to admit evidence of the defendant’s prior hostility toward the complaining witness. See Wigmore, supra §§ 395-96. The fact that the evidence of the prior emotion (be it hostility or sexual desire) involves criminal conduct does not affect its admissibility. Wigmore, supra §§ 216, 398.
I particularly note that the majority’s opinion in no way limits or questions either Commonwealth v. Boulden, 179 Pa.Super. 328, 116 A.2d 867 (1955), or Commonwealth v. Bradley, 243 Pa.Super. 208, 364 A.2d 944 (1976). Those decisions adhere to the principle that in a prosecution for a sexual offense the Commonwealth may not introduce evidence that the defendant committed prior or subsequent offenses against third persons similar to the offense committed against the complaining witness, if its only purpose is to show that the defendant is generally lustful or sexually depraved. It is hornbook law that evidence of prior criminal acts is admissible if “[t]o show a passion or propensity for illicit sexual relations with the particular person concerned in the crime on trial,” McCormick on Evidence § 190 at 449 (Cleary ed. 1972) (footnote omitted); it is also hornbook law that evidence of “[ojther like sexual crimes with other persons do[es] not qualify for this purpose.” Id. (footnote omitted). See also Wigmore, supra § 402(c) (“The defendant’s former rape or attempt at rape of a third person cannot be treated as indicating a passion or desire for the woman in issue. . . . ” (original emphasis).
*321In the present case the Commonwealth presented evidence only of incestuous relations between the complaining witness and appellant, on a regular and continuous basis over a period of four years immediately prior to the incident in question. Thus, this case falls squarely within the principles set forth above.
I also note that this is not a case in which otherwise admissible evidence should be excluded because of its prejudicial nature. Given the complaining witness’s limited intelligence and the fact that she was the principal witness to the crime,* the probative value of the evidence of her prior incestuous relations with appellant was not outweighed by “the danger that it [would] stir such passion in the jury as to sweep them beyond a rational consideration of guilt or innocence of the crime on trial.” McCormick, supra § 190 at 453-54 (footnote omitted).
With these understandings, I join in the majority’s opinion.
A sister of the complaining witness testified that she saw appellant enter a bedroom with the complaining witness, and later saw the top part of him through a window as he was apparently getting off the complaining witness. But this witness, whose testimony was vague, evidently did not directly observe incestuous relations between the parties.