There were also disputes that existed during the times of the Beis Hamikdosh.
Example: Hillel and Shamai disagreed whether it was permissible to bring certain individual karbanos on Yom Tov itself. Hillel did bring such a korbon, and talmidim of Shammai were present. The gemora relates that Hillel took steps to conceal his actions from talmidei Shammai. There were probably other areas of disagreement. What is remarkable is that אלו ואלו דברי אלקים חיים. The two sides who disagreed were at total peace with each other, freely marrying into each others’ families, etc. Today, the questions before a shidduch about whether the other side uses the Eruv or not are plainly sickening and divisive.