You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Samurai

Context:
In the same war, the Prussian Edward Schnell served the Aizu domain as a military instructor and procurer of weapons. He was granted the Japanese name Hiramatsu Buhei (平松武兵衛), which inverted the characters of the daimyo's name Matsudaira. Hiramatsu (Schnell) was given the right to wear swords, as well as a residence in the castle town of Wakamatsu, a Japanese wife, and retainers. In many contemporary references, he is portrayed wearing a Japanese kimono, overcoat, and swords, with Western riding trousers and boots.

Question:
Who did Edward Schnell work for?

the Aizu domain