Shotoku supposedly lived around the year 600, so a long time ago indeed. The first records we have of buddhist texts and artefacts being brought to Japan from Korea are from around 550, and it was during Shotoku's time that the first big temples and such were built. He is credited with building the Horyuji, for example, which is the oldest wooden building in Japan or somesuch.
For those interested, I wrote a few short translations of excerpts from the Shotoku biography found in a text called the Nihon Ojo Zenden from 1882, included below. The first two excerpts are from the beginning and the last one is from the end.
Shōtoku Taishi was the second child of the Emperor Toyohi. In a dream of his mother the Empress, there was a golden coloured monk who said, “I have made a vow to save the world, [therefore] I wish to reside in your womb." The Empress asked, “Who are you?” The monk said, "I am the bodhisattva who saves the world, my home is in the west." The Empress answered, "My belly is not pure, what could reside there?" The monk said, "I have no issue with impurity, I simply feel hope for mankind." He jumped into her mouth, and immediately after it felt as though she had swallowed something.
After this she realised that she was finally pregnant, and she went to eight months. From within her womb, those outside could hear a voice. At the birth, suddenly a yellow and red light arrived which shone from the west and into the palace.
From birth the child had the ability to speak. [During this period] all the people from the Kingdom of Paekche (in Korea) brought sutras and śastras. The Prince said to the Emperor, "I wish to open and inspect them". The Emperor was puzzled and said "Long ago [he must have] lived in China at the Southern Peak and for long periods studied the way of the Buddha".
At the time the Prince was six years old, his body smelled fragrantly, and a person who embraced him would smell fragrant also, a smell which would not go away for many months. [From] Paekche, Nichira came to visit Kōmyō. The Prince was wearing clothes like most children. On a day he went into the palace to look around, Nichira pointed at the Prince and said, "this is a divine being".
In the whole country, old as well as young felt sorrow [as though they had lost] a beloved child. The roads were filled with the wailing voices of mourning. […] The bodies of the Prince and the Empress smelled fragrantly as they had done in life. Both the bodies [became] light like fabric. When the Korean monk Eji heard of the Prince's death, he was grief-stricken and made a vow. He said, "The Japanese Prince was truly a great sage. I, although I am from a different country, feel as the people here do. What benefit can there be from being left alone in this aimless life? On the day of the Prince's death, I will surely die and be with the Prince in the Pure Land." On the twenty-first day of the second month of the following year, on the day of the Prince's death, Eji achieved his death just like he had said.