Under Mamluk rule, the Jewish population of Alexandria began to decline. Meshullam of Volterra, who visited it in 1481, states that he found only 60 Jewish families, but reported that the old men remembered the time when the community numbered 4,000. In 1488, Obadiah of Bertinoro found 25 Jewish families in Alexandria. Following the Alhambra Decree of 1492 a large number of Sephardic Jews immigrated to Alexandria The historian Joseph Sambari mentions an active Jewish community in Alexandria during the 17th century. After the Chmielnicki massacres, some Ukrainian Jews settled in Alexandria. In the 1660s some members of the community began to follow Shabbetai Zvi, while the majority adamantly opposed him. In 1700, some Jewish fishermen from Rosetta moved to Alexandria in hopes of better economic opportunities. During the French conquest of Egypt, Napoleon imposed heavy fines on the Jews and ordered the ancient synagogue, associated with the prophet Elijah, to be destroyed. Under the rule of Muhammad Ali of Egypt, Jews began to experience great social and economic development.