This chapter examines late antique Armenia, focusing on its architectural developments, Christianisation and regional influences. It traces the evolution of Armenian church architecture between the fourth and seventh centuries, emphasising connections with Rome, Persia and Byzantium. The chapter discusses key archaeological findings, including churches, funerary monuments and inscriptions. Major sites like the basilica of Ereroykʿ, the church of Hṙipʿsimē and the patriarchal complexes of Duin and Zuartʿnocʿ reveal a shift from simple basilicas to complex domed designs. The chapter discusses innovations such as tetraconch and triconch plans and explores the role of elite patronage in church construction, as seen in the princely complex of Aruč. Rather than depicting Armenia as an isolated frontier, it argues that its architecture reflects strong ties with Syrian, Byzantine and Iranian traditions. Sculptural decoration, inscriptions and building techniques illustrate these cultural exchanges. While political shifts influenced construction, ongoing excavations continue to shape our understanding of Armenia’s late antique landscape. The chapter stresses the need for further archaeological research, particularly in under-explored areas, to provide a fuller picture of the region’s historical development.