Je me suis donc trompé, ça me rassure !
Ceci va peut-être t'aider, alors :
1st I, P (for prima), PRIMA, A (alpha), OFF P (officina prima)
2nd II, S (for secunda), SECVNDA, B (beta), OFF S (officina secunda)
3rd III, T (for tertia), TERTIA, C, Γ (gamma)
4th IIII, Q (for quarta), QVARTA, D, ∆ (delta)
5th V, E (epsilon)
6th VI, ς (stigma - archaic Greek letter resembling S)
7th VII, Z (zeta)
8th H (eta)
9th N, Θ (theta), DE (delta epsilon)
10th X, I (iota)
11th XI, IA (iota alpha), AI (alpha iota)
12th XII, IB (iota beta), BI (beta iota)
13th ΙΓ (iota gamma), ΓΙ (gamma iota)
14th Ι∆ (iota delta), ∆Ι (delta iota)
15th IE (iota epsilon), EI (epsilon iota)
Source :
Chart of Officina Numbers