You could read about the Quartodecimanism controversy which was the most obvious.
http://en.wikipedia.org/wiki/Quartodecimanism
Traditional Christianity moved away from observing the holy days of Jesus Christ primarily because the Jewish people revolted against the Roman Empire a number of times. Hatred of Jews and anything Jewish by Romans become fashionable and many Christians did not wish to be seen as jews so they stopped doing things that might tie them to Jews. The most obvious of these would be observing the same days as jews.
Eventually it became heresy for a Christian to keep the same days as jews and those who did honor the Lord by honoring his holy days dropped out of "official" church history.
LOL, “quartodecimanism” had nothing at all to do with keeping the OT feasts and EVERYTHING to do with what day to celebrate Easter on.
it was a dispute among Catholics, who did not keep the 7th day Sabbath, nor the Jewish feast days.
nice try!