In this book I will discuss the study of the circular church west of Pelusium. It has an unique style in the architecture of churches, especially in Egypt. This circular church is considered the only discovered in Egypt and there is no church like this in Egypt. I will mention: the role of Sinai in the transmission of Christianity to Egypt from Palestine; the spread of monasticism; the most important Christian places in both south and north Sinai; the role of Sinai in the flight of the Holy family to Egypt especially Pelusium city. And I will talk about the most important Saints of Pelusium, the main planning of the churches and their important styles. Then I will explain the circular church in the light of the excavations, their location, their history, their baptistery and their architectural description especially the eastern (Rotunda) and western building (crypt). Then I will explain the Excavations to the east of the circular church.