Gaza was an ancient gateway to Palestine on the road to Egypt. Gaza was one of five Philistine cities along the southern coast that successfully resisted Israelite conquest until Judah Maccabee's brother Jonathan captured it [ca 150 BCE]. It was virtually destroyed by Alexander Jannai for revolting [ca 96 BCE]. But it was rebuilt as a Roman city by Gabinius. In Acts [8:26] it is the setting for Philip's conversion of an Ethiopian eunuch. But it was more than 300 years before it became a center for Christians.
Gaza first appears in the Tanach as a Philistine city, the site of Samson's dramatic death. Jews finally conquered it in the Hasmonean era, and continued to live there. Notable residents include Dunash Ibn Labrat, and Nathan of Gaza, advisor to false messiah Shabtai Zvi. Gaza is within the boundaries of Shevet Yehuda in Biblical Israel (see Genesis 15, Joshua 15:47, Kings 15:47 and Judges 1:18) and therefore some have argued that there is a Halachic requirement to live in this land. The earliest settlement of the area is by Avraham and Yitzhak, both of whom lived in the Gerar area of Gaza. In the fourth century Gaza was the primary Jewish port of Israel for international trade and commerce.
Sources: Into His Own