From Chabad (linked below, all emphasis mine).
History of Tiberias
Herod Antipas, son of Herod the Great, built the city in 17 BCE, naming it in honor of the Roman emperor Tiberius. Tiberias became the capital of the Galilee, replacing nearby Tzippori. The new city was set in a beautiful locale, along the shore of the Kinneret, near natural mineral hot springs with health giving properties.
However,
it was also the site of an ancient cemetery.
As such it was ritually unclean,
and Jews refused to live there. Antipas forced some Jews from the Galilean countryside to move into his showcase town, but for the next two centuries most Jews shunned Tiberias.
Meanwhile, the Jewish nation was undergoing a crisis. In 69 CE, Jerusalem and the Second Temple were destroyed. Shortly before Jerusalem was destroyed, Rabbi Yochanan ben Zakkai snuck out of the besieged city and established Yavneh as the new center for Jewish learning and leadership (click here for the full story), a response which later inspired German poet Heinriche Heine to call the Torah the "portable homeland of the Jew."
For the next seventy years, the Sanhedrin would meet in Yavneh and then later in the small agricultural village of Usha. After the Bar Kochba rebellion was quashed in 135 CE, virtually all Jewish life was wiped out of the entire southern Judean region. At this point, the Jewish center moved to the northern Galilee region.
Rabbi Shimon bar Yochai purified Tiberias of its graves (see below), and Tiberias, as well as neighboring Tzippori, became the main centers of Jewish learning and culture.
Following the death of Rabbi Judah the Prince in c. 220, the Sanhedrin made its final migration from Tzippori to Tiberias. From then on, Tiberias would remain the center of the diminished Jewish society of the land of Israel until the tenth century.
In 358, following another Jewish revolt (known as the War against Gallus) the Roman emperor disbanded the Sanhedrin. Despite these persecutions,
the sages worked on compiling the Talmud.
Around 400,
the "Jerusalem Talmud" was canonized in Tiberias.
In the latter half of the millennium, Tiberias, now under Muslim control,
was the home of the Masoretes (Mesorah means "transmission"), scholars who were concerned with the accurate transmission of the biblical texts.
These grammarians also introduced the vowel notation system for Hebrew that is still used today. The Aleppo Codex, which can now be seen in the Shrine of the Book in Jerusalem, is credited to the greatest of the Masoretes, Aaron ben Asher. During this era, Tiberias was struck by several major earthquakes which devastated most of the city.
Chabad - Tiberias
Rabbi Shimon bar Yochai spent thirteen years in a cave hiding from the Romans. Due to a dearth of clothing, he spent most of the time buried up to his neck in sand. As a result, his skin wasn't in great condition when he finally left the cave, so he went to bathe in the hot springs of Tiberias and was cured. When he gratefully asked the people of Tiberias what he could do for them,
they asked him to find a remedy for the city's ritual impurity,
so that Jews would want to come and live there.
He miraculously caused all the corpses in the city to rise to the surface of the ground,
and they were removed.
Chabad - Tiberias
Other sources say this was a kabbalistic ritual to raise the dead so that the bodies could be buried elsewhere.
The Synagogue at Tiberias:
Sol / Helios
Mosaic Decoration at the Hammath Tiberias Synagogue
Tiny cube-shaped pieces of cut stone and glass combine to form a mosaic image of a god, a beautiful young male with curly hair and a radiant crown of seven rays of light. He raises his right hand as if signaling his mastery of the cosmos. In his left hand, he holds an orb (representing the sun) and a whip to urge his horses forward. He once stood in a quadriga, a chariot pulled by four horses, now destroyed by the later addition of a wall, though their hooves can still be seen. This 4th-century mosaic depicts the indomitable Roman sun god Sol, known in Greek as Helios.
Mosaic Decoration at the Hammath Tiberias Synagogue
So then, they rejected the Meshiah but had no problem with the Greek and Roman sun gods, Helios and Sol. Then they raised the dead with a kabbalistic ritual because the city they desired to dwell in was built on a cemetery by Herod Antipas. Then they exhumed all the bodies and bones and buried the former bodies of the formerly dead somewhere else, proclaimed the city to be cleansed, set up shop, and sat down to finalize the Jerusalem Talmud and begin working on the Masoretic Text.
You and I have entirely different ideas about what is Qodesh.