Making all allowances for conventional exaggerations, it is clear from the correspondence that there was deep love between Marcus and his preceptor. The letters cover several years in succession, but soon after the birth of Marcus's daughter, Faustina, there is a large gap. It does not follow that the letters ceased entirely, because we know part of the collection is lost; but there was probably less intercourse between Marcus and Fronto after Marcus took to the study of philosophy under the guidance of Rusticus.