The common characteristics of Family 13 were initially identified in a group of four witnesses; but the category has subsequently been extended, and some authorities list thirteen family members. The most obvious characteristic of the group is that these manuscripts place John 7:53-8:11 after Luke 21:38.
The four minuscules Ferrar collated are:
Ferrar transcribed three of these minuscules himself, accepting a previous transcription of 69 done by another person as trustworthy and adequate. The result of his work demonstrates that the members of Family 13 do indeed seem to share a common pattern of deviations from the accepted Greek texts of antiquity.
By 1941, Kirsopp and Silva Lake turned their attention to this important family of manuscripts. In their work on the Gospel of Mark entitled Family 13 (The Ferrar Group): The Text According to Mark, the family is characterized as consisting of 10 manuscripts (13, 69, 124, 346, 543, 788, 826, 828, 983, and 1689).
In this essay, the Lakes thoroughly cover all that was then known about the provenance of each of these manuscripts. Many of the manuscripts proposed as belonging to Family 13 appear to have links to Calabria and Albania; manuscripts 124 and 174 being recorded as having been written in Calabria, and most of the family members recording menologion readings for Calabrian saints. Some family members have common supplemental geographical material that appears to derive from a 7th century original.
Today, the family supposedly consists of thirteen members (13, 69, 124, 174, 230, 346, 543, 788, 826, 828, 983, 1689, and 1709), although the most recent work of Drs. Barbara Aland, Klaus Wachtel, and others at the Institut für neutestamentliche Textforschung in Münster, Germany, imply that some of these family members are more similar to the majority Byzantine Text, and therefore should not be included in this family at all. Codex 1709 is held in the national archive at Tirana, Albania; which also holds some 46 other medieval Greek New Testament manuscripts, most of which remained uncollated and unpublished until 2008 - when they were photographed by a team from the Centre for the Study of New Testament Manuscripts. A press release from CSNTM in March 2008 reported that "one or two" of these previously unstudied manuscripts may also belong to family 13; in which case they would be the earliest surviving witnessess to this text.
In 1924 Burnett Hillman Streeter proposed that Family 13 should be classified as one branch of a distinct Caesarean text-type, differing in a number of common respects from the then established Byzantine, Western and Alexandrian text-types. This view is supported by some, but not all, subsequent scholars.