Tenno-ji, as this temple is popularly known, is one of the most important historic sights in Osaka and the oldest temple in Japan. Founded in 593, it's been destroyed by fire many times. The last reconstruction of the five-story pagoda in 1965 has maintained the original design and adhered to the traditional mathematical alignment. What has managed to survive from earlier times is the 1294 stone torii (gate) that stands at the main entrance. (Interestingly enough, these are rarely used at Buddhist temples.)
The founder, Umayado no Mikoto (573–621), posthumously known as Prince Shotoku (Shotoku Taishi), is considered one of early Japan's most enlightened rulers. He was made regent over his aunt, Suiko, and set about instituting reforms and establishing Buddhism as the state religion. Buddhism had been introduced to Japan from China and Korea in the early 500s, but it was seen as a threat to the aristocracy, who claimed prestige and power based up their godlike ancestry. On the 21st of every month the temple hosts a flea market that sells antiques and baubles; go in the morning for a feeling of Old Japan.