Judaism, as every religion, has different branches. There are reform, conservative, and orthodox Judaism. Orthodox Judaism in its turn has several movements.

Hasidic Judaism is one movement within Haredi Judaism, the most theologically conservative stream of Orthodox Judaism, which appeared in 18th century. 

The core idea of Hasidism was that G-d's presence was in all of one's surroundings and that one should serve G-d in one's every deed and word.

Ukraine is known to be the birthplace of Hasidism. The founder of Hasidism was Rabbi Israel ben Eliezer Baal Shev Tov, who lived in the Ukrainian town of Medzhybizh in 1742 - 1760. His great-grandson Rabbi Nachman of Breslov (1772–1810) founded the Breslov branch of Hasidic Judaism. 

He strongly encouraged his followers to spend each Rosh Hashana with him in the town of Breslov. Hundreds of followers would gather for the holiday prayer service, festive meals, and special Torah lessons taught by the Rabbi. When asked why Rosh Hashana was so significant, Rabbi Nachman explained, "My Rosh Hashana is greater than everything. I cannot understand how it is that if my followers really believe in me, they are not all scrupulous about being with me for Rosh Hashanah. No one should be missing! Rosh Hashanah is my whole mission."

Devout Breslovers started visiting Uman to pray at Rabbi Nachman’s grave in 1811, the year after his death. While they came at different times of the year, Rosh Hashanah, in the early fall, soon became a focal point for the pilgrimage.

 

The Rosh Hashana pilgrimage ground to a halt with the Bolshevik Revolution of 1917, which sealed the border between Russia and Poland. Uman became a "closed city" and foreigners were strictly prohibited from entering.

Despite the Communist ban on public prayer gatherings, Breslover Hasidim in USSR continued to gather clandestinely every Rosh Hashanah during the 1920s and 1930s. In 1934, the Soviets ostensibly granted permission for 28 Hasidim to travel to Uman for Rosh Hashanah. In fact, it was a ruse to discover their identities — 16 were murdered while still in Uman and 12 were exiled to Siberia. Only four of the exiles survived.

World War II and the Holocaust decimated the numbers of Breslover Hasidim living in USSR. The Rosh Hashana pilgrimage resumed on a drastically smaller scale in 1948, when 11 Hasidim independently traveled from cities throughout USSR to Uman for Rosh Hashanah. 

During the USSR, as the public prayer was prohibited, the pilgrimage could not have take place in big scales, however it did took place clandestinely in smaller scales. Until 1989, several hundred American and Israeli Hasidim made their way to Uman, both legally and illegally, to pray at the grave of Rabbi Nachman. Sometimes the government issued individual tourist visas to Uman, but no one was allowed to stay in the city overnight. The pilgrimage restarted in 1989, when about 800 Hasidim gathered in Uman for Rosh Hashanah. Now up to 30 000 Hasidim arrive to the grave of Rabbi Nachman in Uman to celebrate Rosh Hashanah each year.