Pre-Zionist resettlement in Palestine met with various degrees of success. For example, little is known of the fate of the 1210 "aliyah of the three hundred rabbis" and their descendants. It is thought that few survived the bloody upheavals caused by the Crusader invasion in 1229 and their subsequent expulsion by the Muslims in 1291. After the fall of the Byzantine Empire in 1453 and the expulsion of Jews from Spain (1492) and Portugal (1498), many Jews made their way to the Holy Land. Some Ukrainian Jewish refugees fleeing the pogroms of the Khmelnytsky Uprising of the mid-17th century also settled in the Holy Land. Then the immigration in the 18th and early 19th centuries of thousands of followers of various Kabbalist and Hassidic rabbis, as well as the disciples of the Vilna Gaon and the disciples of the Chattam Sofer, added considerably to the Jewish populations in Jerusalem, Tiberias, Hebron, and Safed.