I started to read The Alchemist (both in Japanese and English) and I'm not able to understand the meaning of といった in this sentence: 少年の名はサンチャゴといった。 The equivalent of that sentence in the English version is "The boy's name was Santiago".
"The boy's name was called Santiago". Or you could think of it as "So far as the boy's name was concerned, he was called Santiago". I don't think a native-speaker would worry over-much about what the "subject" of といった is, although English rather forces the question on us.
This was ordinary usage in English at one time. In the King James Version of the Bible the account of Jesus's circumcision/naming ceremony has "His name was called Jesus" where more modern translations have "He was named Jesus".