This is a direct appeal from the judgment of sentence entered by the Court of Common Pleas of Philadelphia County on September 11, 1979. According to the factual posture of the case, at 2:30 p. m. on December 4, 1978, appellant pierced the throat of Harry Parness with an ice pick and robbed him. At the time of the incident, Mr. Parnell was managing a parking garage at 2031 Lombard Street in the City of Philadelphia. Following a non-jury trial, appellant was. convicted of possession of an instrument of a crime, ^[1] robbery ^[2] and simple assault. ^[3] Post verdict[*3] motions were denied and appellant was sentenced to concurrent prison terms of one to three years on each count.

Appellant’s allegation that the crimes of robbery and simple assault merge and that the lower court erred in convicting him of both crimes is waived because of appellant’s failure to raise it before the court below. Commonwealth v. Clair, 458 Pa. 418, 326 A.2d 272 (1975); Commonwealth v. Guenzer, 255 Pa.Super. 587, 592, 389 A.2d 133, 135-136 (1978). However, illegality of sentence is not a waivable issue, Commonwealth v. Walker, 468 Pa. 323, 362 A.2d 227 (1976); Commonwealth v. Guenzer, supra, and appellant’s failure to raise this issue does not preclude our present consideration of it. Commonwealth v. Usher, 246 Pa.Super. 602, 371 A.2d 995 (1977).

Commonwealth ex rel. Moszczynski v. Ashe, 343 Pa. 102, 21 A.2d 920 (1941) set forth the standard test 1'or merger of offenses. Therein the Pennsylvania Supreme Court wrote:

The true test of whether one criminal offense has merged in another is not (as is sometimes stated) whether the two criminal acts are ‘successive steps in the same transaction’ but it is whether one crime necessarily involves another, as for example, rape involves fornication, and robbery involves both assault and larceny.

Id., 343 Pa. at 104, 105, 21 A.2d at 921 (emphasis in original). A reading of the above test indicates that a conviction for simple assault merges ^[4] with a conviction for robbery ^[5] for[*4] purposes of sentencing. After the crime of robbery was established no additional facts were necessary to prove simple assault. See also Commonwealth v. Guenzer, supra, and Commonwealth v. White, 250 Pa.Super. 647, 379 A.2d 617 (1977) conviction for simple assault merges with a robbery conviction under 18 Pa.C.S.A. § 3701(a)(1)(h).

Accordingly, the judgment of sentence for simple assault is vacated, and the case is remanded to the lower court for resentencing on the robbery conviction. ^[6]