Complex sentence: Although Cicero in his writings is mostly hostile toward Epicureanism, his dear friend Atticus was an Epicurean, and it should be noted that this remark, occurring within a dialogue, is attributed to the interlocutor Varro.
Split into simpler sentences: Although Cicero in his writings is mostly hostile toward Epicureanism, his dear friend Atticus was an Epicurean. This remark, occurring within a dialogue, is attributed to the interlocutor Varro.