The origin and date of establishment of the
Noumeroi is unknown. They are first securely attested during the reign of
Michael III (r. 842–867): the unit is mentioned in the
Taktikon Uspensky of 842/843, and the name of one of its commanders, Leo Lalakon, also survives from the same period.
J.B. Bury considered a seal of the 7th–8th centuries mentioning a "
droungarios tou nou[merou?]" as an indication of a predecessor of the 9th-century unit, and based on the nomenclature of its subaltern officers hypothesized an origin in the
East Roman army of the 6th century, while
John Haldon traces its hypothetical lineage to the late 7th century. The precise title of this unit remains uncertain. In Byzantine literature it is documented only in the genitive plural (τῶν Νουμέρων), which leaves unclear whether the unit title was
Noumeroi (Νούμεροι) or
Noumera (Νούμερα). Modern scholars over the past century have variously favoured both forms. The term
noumeros (transliterated from , in Greek also translated as
arithmos) was itself a common term for a regular military unit of indeterminate size used in
Late Antiquity. It was only later, in the 8th and possibly even in the 9th century, that the name came to specify this particular unit. The regiment in turn gave its name to the
Noumera, a building adjoining the
Hippodrome of Constantinople that served as their barracks and as a city prison. The French scholar
Rodolphe Guilland identified the 9th-century Noumera with the prison known as Prandiara in earlier times. The
Noumeroi ranked among the imperial
tagmata, professional regiments stationed in and around
Constantinople. Unlike most of the
tagmata, the
Noumeroi were composed of infantry and never left Constantinople, being entrusted with guard duties in the city, specifically watching over the Noumera prison and sharing the protection of the
Great Palace of Constantinople with two other
tagmata, the
Vigla or
Arithmos, a cavalry unit which accompanied the emperor on campaign, and another infantry unit under the Count or Domestic of the Walls (
komēs/domestikos ton teichōn). The latter had close ties with the
Noumeroi: they shared a common function and had the same internal structure, and until the reign of Michael III at least, the two commands seem to have been combined under a single officer, as attested in the person of a certain Nikephoritzes during this time. == Command structure ==