Apologetics (from Greek ἀπολογία, "speaking in defense") is the religious discipline of defending religious doctrines through systematic argumentation and discourse. Early Christian writers (c. 120–220) who defended their beliefs against critics and recommended their faith to outsiders were called Christian apologists. In 21st-century usage, apologetics is often identified with debates over religion and theology. The term apologetics derives from the Ancient Greek word apologia (ἀπολογία). In the Classical Greek legal system, the prosecution delivered the kategoria (κατηγορία), the accusation or charge, and the defendant replied with an apologia, the defence. The apologia was a formal speech or explanation to reply to and rebut the charges. A famous example is Socrates' Apologia defense, as chronicled in Plato's Apology. In the Koine Greek of the New Testament, the Apostle Paul employs the term apologia in his trial speech to Festus and Agrippa when he says "I make my defense" in Acts 26:2. A cognate form appears in Paul's Letter to the Philippians as he is "defending the gospel" in Philippians 1:7, and in "giving an answer" in 1 Peter 3:15. Although the term apologetics has Western, primarily Christian origins and is most frequently associated with the defense of Christianity, the term is sometimes used referring to the defense of any religion in formal debate involving religion. Baháʼí apologetics Many apologetic books have been written in defence of the history or teachings of the Baháʼí Faith. The religion's founders wrote several books presenting proofs of their religion; among them are the Báb's Seven Proofs and Bahá'u'lláh's Kitáb-i-Íqán. Later Baháʼí authors wrote prominent apologetic texts, such as Mírzá Abu'l-Fadl's The Brilliant Proof and Udo Schaefer et al.'s Making the Crooked Straight. One of the earliest Buddhist apologetic texts is The Questions of King Milinda, which deals with the Buddhist metaphysics such as the "no-self" nature of the individual and characteristics such as wisdom, perception, volition, feeling, consciousness and the soul.