original_query: Who were Alp Tigin's vassals in the Samanid empire?
query: Who were Alp Tigin's vassals in the Samanid empire?
answer: The provided text mentions Alp Tigin as a nominal vassal of the Samanids himself, not as someone with vassals.  The text states that he conquered Ghazna in 962 and his successors, including Sebük Tigin, continued to rule as Samanid "governors".