This is the 4750th most frequent Spanish word.
conocían
"(They/You all) knew" – imperfect tense of "conocer."
The word 'conocían' is the imperfect form of 'conocer', used here to describe a past habitual state of familiarity with the neighborhood.
Ellos conocían el vecindario porque vivieron allí durante muchos años.
They were familiar with the neighborhood because they had lived there for many years.
The word 'conocían' is used in its reflexive form 'se conocían', indicating mutual acquaintance in the past.
No se conocían al inicio del curso, pero ahora son buenos amigos.
They didn't know each other at the beginning of the course, but now they are good friends.
In this sentence, 'conocían' is used to describe the historians' ongoing familiarity with the ancient writings in the past.