From the book Ancient Egypt In Lace and Color.
The ancient Egyptians linked the myth of the phoenix with immortality. According to legend, the Bennu bird created itself from a fire in a holy tree in the temple of Ra. The Egyptians considered this bird’s rise from the ashes to be symbolic of the Nile river’s annual flooding, which left the soil fertile again for the next farming season.
The Bennu bird had two long feathers on its crest and was often depicted with the sun disk crowning its head.