In Acts 29 the Jewish Christian Elders in Jerusalem sent a letter to the gentile believers throughout the world, instructing them to be at peace, and stating that they were not required to follow Jewish tradition.
For it has seemed good to the Holy Spirit and to us to lay on you no greater burden than these requirements: that you abstain from what has been sacrificed to idols, and from blood, and from what has been strangled, and from sexual immorality. If you keep yourselves from these, you will do well. Farewell. Acts 15:28-29 ESV
This is obviously in response to the circumcision party, and it's fairly obvious that they're saying circumcision and the dietary laws were not required of gentiles, but it doesn't seem to saying anything about the laws we still consider core (murder, covetousness, stealing, etc).
Was there some implicit set of laws that was not referenced, but would be understood by both parties to be in effect?