er Theodosius the Great or Theodosius II. is
uncertain). He probably did not know Greek; his references to Greek
authors do not imply this. Though certainly Irish by birth, it has been
conjectured (from his references to Sedulius and the caliph's elephant)
that he was in later life in an Irish monastery in the Frankish empire.
Letronne inclines to identify him with Dicuil or Dichull, abbot of
Pahlacht, born about 760.

There are seven chief MSS. of the _De mensura_ (Dicuil's tract on
grammar is lost); of these the earliest and best are (1) Paris,
National Library, Lat. 4806; (2) Dresden, Regius D. 182; both are of
the 10th century. Three editions exist: (1) C. A. Walckenaer's, Paris,
1807; (2) A. Letronne's, Paris, 1814, best as to commentary; (3) G.
Parthey's, Berlin, 1870, best as to text. See also C. R. Beazley,
_Dawn of Modern Geography_ (London, 1897), i. 317-327, 522-523, 529;
T. Wright, _Biographia Britannica literaria, Anglo-Saxon Period_
(London, 1842), pp. 372-376. (C. R. B.)

DIDACHE, THE, or _Teaching of the (twelve) Apostles_,--the most
important of the recent recoveries in the region of early Christian
literature (see APOCRYPHAL LITERATURE). It was previously known by name
from lists of canonical and extra-canonical books compiled by Eusebius
and other writers. Moreover, it had come to be suspected by several
scholars that a lost book, variously entitled _The Two Ways_ or _The
Judgment of Peter_, had been freely used in a number of works, of which
mention must presently be made. In 1882 a critical reconstruction of
this book was made by Adam Krawutzcky with marvellous accuracy, as was
shown when in the very next year the Greek bishop and metropolitan,
Philotheus Bryennius, published _The Teaching of the Twelve Apostles_
from the same manuscript from which he had previously published the
complete form of the Epistle of Clement.[1]

_The Didach[=e]_, as we now have it in the Greek, falls into two marked
divisions: (a) a book of moral precepts, opening with the words, "There
are two ways"; (b) a manual of church ordinances, linked on to the
foregoing by the words, "Having first said all these things, baptize,
&c." Each of these must be considered separately before we approach the
question of the locality and date of the whole book in its present form.

1. _The Two Ways._--The author of the complete work, as we now have it,
has modified the original _Two Ways_ by inserting near t