The soldiers confiscated food from the people they had conquered.
Literal
Soldiers [topic-は] they [subject-が] conquered people [from-から] food [object-を] confiscated.
Features a relative clause (彼らが征服した) modifying 人々 — in Japanese the modifying clause precedes the noun with no relative pronoun. 没収する and 征服する are formal Sino-Japanese compounds giving this a written, reportorial tone.