If the coin is legit I would suspect early posthumous issue. Others are correct when they say the coin is faked often. Off the rip based on the pics, I would suspect the coin is authentic. The Monogram in the reverse left field looks like greek "L" which could indicate Amphipolis mint. To determine the exact date and issuing authority as well as authenticity you need...
A) nice clear pics of both sides.
B) The weight and diameter of the coin. This will help determine denomination and dating. Lifetime issues are generally very heavy 17 g ish and on a smaller chunky flan. Later issues maintained the approx weight but increased the flan size from about 25 mm to about 32 mm. The legs are uncrossed which suggests lifetime but the title indicates an early posthumous issue. approx. 315 - 294 BC. Although there are exceptions to this convention.
C) you need to tell us that you did not buy it from a "market vendor" in Turkey. If that is the case there is like a 99% chance it is a modern fake.