Identifying the "oldest church" depends on whether you mean the oldest building used for worship or the oldest purpose-built structure. The Dura-Europos church in Syria, dated to approximately 233 AD, is often cited as the oldest known house-church; it was originally a private home converted for Christian gatherings and contains some of the earliest known Christian frescoes. However, the Megiddo Church in Israel, discovered within the grounds of a prison, features a prayer hall with mosaics dating to the early 3rd century (roughly 230 AD), making it a strong contender for the oldest remains of a Christian worship site. For purpose-built structures, the Aqaba Church in Jordan (circa 293–303 AD) is recognized as one of the earliest examples of an official church building designed specifically for that role. Additionally, the Etchmiadzin Cathedral in Armenia, completed in 303 AD, is widely considered the oldest cathedral in the world, marking Armenia's history as the first nation to officially adopt Christianity as its state religion.