user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: Which ruler was the topic of the sculpture Diocletien Vaux1? 
Knowledge Triplets: Split, travel.travel_destination.tourist_attractions, Cathedral of Saint Domnius
Diocletian, freebase.valuenotation.is_reviewed, Place of death
Diocletian, freebase.valuenotation.is_reviewed, Date of death
Diocletian, people.person.children, Galeria Valeria
Diocletian, people.deceased_person.place_of_death, Split
Diocletian, symbols.name_source.namesakes, Diocletian's Palace
Diocletian, freebase.valuenotation.is_reviewed, Place of birth
Diocletian, people.person.spouse_s, m.0j4l7hx
Galeria Valeria, people.person.parents, Diocletian
Diocletian, common.topic.article, m.02d0w
Diocletian, freebase.valuenotation.is_reviewed, Date of birth
Split, location.location.contains, Diocletian's Palace
Diocletian, symbols.name_source.namesakes, Baths of Diocletian
Diocletian, people.person.place_of_birth, Solin, Croatia
Diocletian, people.person.nationality, Roman Empire
Split, travel.travel_destination.tourist_attractions, Diocletian's Palace
Diocletian, freebase.valuenotation.is_reviewed, Gender
Diocletian, people.person.religion, Paganism
Diocletian, fictional_universe.person_in_fiction.representations_in_fiction, Diocletian
Diocletian, freebase.valuenotation.is_reviewed, Country of nationality
Diocletien Vaux1, common.image.appears_in_topic_gallery, Diocletian
m.0j4l7hx, people.marriage.spouse, Diocletian
Diocletian, people.person.gender, Male
Diocletian, people.deceased_person.place_of_burial, Cathedral of Saint Domnius
Diocletian, freebase.valuenotation.has_value, Height
Diocletian, common.topic.image, Diocletian
Diocletian, common.topic.notable_types, Monarch
Diocletian, common.topic.image, Diocletien Vaux1
Diocletien Vaux1, common.image.size, m.0h05b4_
Diocletian, common.topic.notable_for, g.1257t42wh
Diocletian, freebase.valuenotation.has_value, Parents

Answer: Roman emperor