7464
Under Emperor John I Tzimiskes ( r. 969 – 976 ) , a doux who commanded the professional tagmatic troops stationed in the theme was installed in the city , and seems to have co-existed for a while with the strategos , before assuming the latter 's duties as well .
 person: John I Tzimiskes
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: John I Tzimiskes