In the teacher's letter in cap. XXIII of Orberg's Lingua Latina Per Se Illustrata Pars I Familia Romana, it says,
Scribebam Tusculi Kalendis Iuniis. Hic dies me monet de pecunia quam mihi debes.
Why is the imperfect 'scribebam' used here? I would translate this as, 'I wrote (this letter) in Tusculum on the first of July.' In my opinion, the imperfect does not make much sense here since it is a statement of fact and a completed action at a definite point in time and it is not contrasted with another clause as in an ongoing action that was interrupted by another or something continuous or habitual.
But maybe I am led astray by the usage of the imperfect in Spanish and French and do not yet fully understand the Latin imperfect. Or maybe this case is special because it is a letter?