I don't know what you mean by the 50 years, but the pharisees were teaching that believing gentiles had to be circumcised and keep the law of Moses to be saved.
Regarding the comment about Pharisees, you're incorrect...there were two different schools of Pharisees. As far as the 50 years... here, take a few minutes to read this.
So there is this dispute, and the leaders of the faith come together, talk it out, and write a letter to the Gentiles. The letter gives a few commands, nothing new as all had been previously recorded in scripture, and that should be about the end of it, right? Well, like so much when it comes to scripture, something that seems simple gets touched by man and turned into a mass of confusion. I hope in the next few minutes, to shed some light on the contents of the Acts 15 letter.
The first thing we need to understand is what started the debate to begin with?
Acts 15:1 and certain men came down from Judea and taught the brethren, "Unless you are circumcised according to the custom of Moses, you cannot be saved." (NKJV)
* In this case, "the custom of Moses" is a reference to Torah(God's law or instruction).
Pretty simple, unless you have been circumcised on the 8th day of your life, you can't be saved. What is wrong here? Well, for starters, YOU weren't commanded to be circumcised on the 8th day of your life. That command was given to your father; obviously, an 8 day old baby isn't performing his own bris. Second, when did physical circumcision save us to begin with? The answer to that is it didn't. Like many aspects of the Tanach (OT), circumcisions, the feasts, the sacrifices...these things were pointing to something to come. They were a type, and we need to determine what the anti-type or shadow is. But that is another note.
What we have here are men from Judea, Jews, and as we see throughout the Apostles Writings, Yehoshua (Jesus) and Paul to an extent, spend a great deal of time rebuking those things which add to Torah or change it. Not every Pharisee was rebuked, and not every tradition external of scripture is rebuked. For example, in John 10:22-39 it appears that to some degree, Yehoshua took part in Hanukkah, the feast or festival of lights. Hanukkah is not a commanded holy day, but it isn't based on pagan origins either. So, we see no rebuke of this extra biblical holiday. No, the rebukes were clearly tied to that which stood against the teachings of scripture. Circumcision unto salvation is not scripture, but we do know where it comes from.
What must I do to be saved a proselyte?
About 50 years before the council of Jerusalem, not too long before the time Yehoshua was born, there was a great debate between the two leading teachers of that day, Hillel and Shamai. Beit Hillel (Beit means house but can also be used as school) taught the spirit of the law and his teachings are pretty well aligned to what Yehoshua taught when he was here. It should be noted that Paul was taught by Gamaliel (Acts 22:3) who was the grandson of Hillel. Beit Shamai on the other hand, taught the letter of the law, a much stricter interpretation of Torah than what Hillel taught.
So, one day these two heavyweights engage in debate about what should be expected of a proselyte. (A convert to Judaism) Hillel took the softer position, saying that a person must abstain from idols, from fornication, from blood and food offered to idols. (Does that all sound familiar?) He also added that a person must know the two great commands, because as Yehoshua said in Matthew 22:40, "all Torah and the Prophets hang on knowing we are to love God and neighbor." (Paraphrased)
Shamai however was more of a hardliner. He also took the same positions Hillel took but he added the need to know ALL 613 commands rather than just the "big two," AND that a proselyte would need to be circumcised in order to become a Jew.
In the end, Shamai's position became hallacha or "Jewish law."
*It should be noted that both men agreed that these were what was expected for the new convert and that the new convert would learn more as they grow.
From this you should be able to see that the men from Judea that confronted Paul and Barnabas were of the school of Shamai or were at least adhering to this 50 year old Jewish law and were applying it to those non-Jews who were following Yehoshua. As a quick side note, we must understand that the first 30-40 years of the faith had gentiles or non-Jews going into the synagogues on Sabbath to hear Torah read. In practice, there was no difference between an orthodox Jew and a Yehoshua following Jew OR gentile. So because the non-Jews were going to the synagogues, many of what we would now call orthodox Jews placed their expectations on these gentiles... and one of those expectations was "get circumcised to be saved."
Is there more than these four?
When the cases had been made before the council, a ruling was handed down and a letter was drafted. It was to be sent to the gentiles/nations, and the main point was:
Act 15:29 that you abstain from things offered to idols, from blood, from things strangled, and from sexual immorality. If you keep yourselves from these, you will do well. Farewell. (NKJV)
Many today, especially in the church, teach that the above was all that was expected of the gentile believer in Yehoshua. Well, as you would expect, I don't agree. Where do we see not to serve another god? Where does it say not to steal? Is it ok to bear false witness now? Obviously, when just a little reason it applied, we can clearly see that there is more that is expected of us than what is written in the Acts 15 letter. I submit that this council convened to right an old wrong! I submit that the same argument that occurred 50 years before this council came together, was argued one more time and reversed. The pagans in this time period fornicated with pagan temple prostitutes, made offerings to idols and ate things sacrificed to idols, etc. By asking that a new gentile believer in Yehoshua to abstain from these things, you were "setting them apart" from their pagan brethren. They clearly were then to be taught what was expected of them, they were to "STUDY to show themselves approved as workman unto God."
I conclude then, that the letter in Acts 15 was the starting point, not the finish line.
Peace to you.
Ken