。
She loved poetry and music.
Literal
She [topic-は] poems [and-と] music [subject-が] liked was.
The particle と here is the listing/comitative と, joining 詩 and 音楽 into a single conjoined noun phrase ('poetry and music'). Unlike や (non-exhaustive 'and others'), と presents an exhaustive list — exactly these two things. The whole phrase 詩と音楽 then takes が because the predicate 好き is a na-adjective of preference. The past form 好きだった frames this as a description of the past — perhaps recalling someone no longer in the speaker's life, or noting a past phase of their tastes.