Why did a breach exist between Jews and Samaritans in Jesus’ day?

 
▪ John 4:9 says that “Jews have no dealings with Samaritans.” The roots of this separation seem to date back to when Jeroboam established idol worship in the northern ten-tribe kingdom of Israel. (1 Kings 12:26-30) 

Samaritans were from Samaria, the capital of the northern kingdom. When the ten tribes fell to the Assyrians in 740 B.C.E., the conquerors settled pagan foreigners in Samaria. Mixed marriages between these settlers and the local people evidently resulted in further corruption of the Samaritans’ worship.
 
Centuries later, the Samaritans opposed the efforts of Jewish returnees from the Babylonian exile to rebuild Jehovah’s temple and Jerusalem’s city walls. (Ezra 4:1-23; Nehemiah 4:1-8) Religious rivalry was heightened when the Samaritans built their own temple on Mount Gerizim, likely in the fourth century B.C.E.
 
In Jesus’ day, the term “Samaritan” carried more of a religious than a geographic connotation and referred to an adherent of the sect that flourished in Samaria. The Samaritans still worshipped on Mount Gerizim, and the Jews had a scornful, disrespectful attitude toward them.—John 4:20-22; 8:48.