The word inculcaban is the imperfect form of inculcar in the third person plural.
See the full inculcar conjugation

inculcar

Los padres y maestros les inculcaban miedo.
Other parents and teachers were instilling fear in the children.
Por ejemplo, encontramos en él ciertas ideas que se hallan en Tronson y en Olier; eran las ideas sobre el sacerdocio y el espíritu eclesiástico que se inculcaban en San Sulpicio.
For example, we find some ideas which are also found in the writings of Tronson and Olier; the ideas in question deal with the priesthood and the ecclesiastical spirit instilled into the seminarians at Saint-Sulpice.
Siempre tenemos la idea de que antaño se inculcaban valores más sólidos.
We are always under the impression that more solid values were instilled in days gone by.
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