Basilides was earlier than Marcion, being the founder of a Gnostic sect at Alexandria in the reign of Hadrian (a.d. 117–138).  His doctrines are described by Irenæus (I. xxvii. 3–7), and very fully by Hippolytus (Refut. omn. Hær. VII. 2–15).  The charge of teaching licentiousness attaches rather to the later followers of Basilides than to himself or his son Isidorus (Clem. Alex. Stromat. III. cap. 1).  Basilides wrote a Commentary on the Gospel in 24 books (Exegetica), of which the 23rd is quoted by Clement of Alexandria (Stromat. IV. cap. 12), and against which Agrippa Castor wrote a refutation.  Origen (Hom. I. in Lucam.) says that Basilides wrote a Gospel bearing his own name.  See Routh, Rell. Sacr. I. p. 85; V. p. 106:  Westcott, History of Canon of N.T. iv. § 3.