St. Theodorus Stratelates, Coptic, Egypt, 9th-10th Century.
Acta martyrum (Acts of Martyrs) f.194r, Biblioteca Apostolica Vaticana. Ms. Vat. Copt. 66.

folio 194v, Biblioteca Apostolica Vaticana. Vat.copt.66

f.210v, St. Theodorus Stratelates, Coptic, Egypt, 9th-10th Century. Biblioteca Apostolica Vaticana. Ms. Vat. Copt. 66.
f.287v, St. Mercurius, Coptic, Egypt, 9th-10th Century. Biblioteca Apostolica Vaticana. Ms. Vat. Copt. 66.

St. Theodorus Stratelates (the general) was first described in the so-called Acts of Augarus in the 9th century. There we read how the saint prepares to fight the dragon which is plaguing his natal city, Euchalta. He comes to the district where the dragon is, and falls down on the grass in sleep. A devout women, Eusebia, warns him of the danger which threatens him. But Theodorus, armed with the sign of the cross and strengthened by prayer, challenges the dragon (while Eusebia weeps) to come out of its lair. The dragon comes out, making the ground tremble under its feet, and is immediately speared by the holy man. Many heathen soldiers who witness this, embrace Christianity. The fact that this St. Theodorus Stratelates (however legendary his existence was next to his original "ego", St. Theodorus Tiro) was venerated by the Copts, is evident from, for example, MSS. of his biographies. Three such MSS. include pen-drawings:

1. Vat. Copt. 66, fol. 210 verso, from the 9th or 10th century
2. Vat. Capt. 58. fol. 191 verso, from the same time.
3. Pierpont Morgan 613, fol. 1 verso, 903 A.D.

These drawings are accompanied by inscriptions, while the horseman is always shown spearing a monster; only in Vat. Copt. 58 is this difficult to see. The first two pen-drawings also show the woman.
Source: p.120, The Central Church of Abdallah Nirqi by By Paul van Moorsel et. al.

Referenced as figure 143 in The military technology of classical Islam by D Nicolle
143. Manuscript from St. Anthony in the Desert, 'Sts. Mercurius and Theodore', 9th-10th centuries AD, Coptic, Bib. Vat. Ms. Copt. 66, ff. 194r, ~~194v~~ [210v] and 287v, Rome (Ler C).

St. Theodorus Stratelates, Coptic, Egypt, 9th-10th Century. Acta martyrum (Acts of Martyrs) f.194r, Biblioteca Apostolica Vaticana. Ms. Vat. Copt. 66.

St. Theodorus Stratelates, Coptic, Egypt, 9th-10th Century.
Acta martyrum (Acts of Martyrs) f.194r, Biblioteca Apostolica Vaticana. Ms. Vat. Copt. 66.