Q: In this task your given a passage in Catalan. you must ask a question in Catalan, that is relevant to the passage. A question that is constructed should be precise and based on factual information from the passage. A constructed question should be: (a) unambiguous (b) be directly answerable from the passage (c) have a unique answer (d) have an answer that is a continuous span of text from the passage. Try to avoid formulating questions that (a) can be answered without referring to the passage, or (b) use exactly the same words or questions given in the passage. Try to make the question fluent in the language used. You have to create exactly one question.
Es considera que formen part del preromànic la banda de ponent de la nau, així com la capçalera trapezoïdal d'un edifici anterior. La volta de canó sobre arcs torals data del segle xi, mentre que la nau de llevant amb creuer, capçalera i la base del campanar daten dels segles xii i xiii. Finalment, el cos del campanar data del segle XVI.[127] Anualment s'hi celebra un aplec el tercer diumenge del mes de maig.[1] 
A:
De quin estil forma part la banda de ponent de la nau?