The famous monumental gateway to the Akropolis is a successor to a Mycenaean building. But what did this Bronze Age gateway, in use up to the 5th century B.C., look like, and what did the architect Mnesikles tear down before he started his construction? This detailed architectural study explores these problems, and reveals the existence of an earlier theatral area for viewing the Panathenaic procession, and some half-built trial runs, below the current Propylon.