北海道や東北地方が「蝦夷地」とされていた頃、東北地方はそこに住む一部の豪族たちが治めていました。
When Hokkaido Island and the northeastern part of Honshu Island were called, “the foreign land”, some of the powerful families residing there were governing the northeastern part of Honshu Island.
朝廷は、天皇（スメラミコト）が統治（すめらいしら）されれば、東北地方の民（おほみたから）の生活の質は大きく向上することを豪族の長たちに説得し続けましたが、頑なにこれを拒み続けられていました。
Although the dynasty had been trying to persuade the heads of the powerful families there that the quality of life would improve so much if the northeastern part of Honshu Island becomes a part of Japan, the offer had been persistently declined.
そこで、朝廷は東北地方の征服を決め、誉れで強大な権限を持つ「征夷大将軍」という職務を新設しました。
Therefore, the dynasty decided to conquer the region by force and to made a honorable and significantly powerful post called, “Seii Great Shogun (General)”.
この点、「征夷」とは「蝦夷地を征服する」という意味です。
“Seii” means “conquering the foreign land”.
