This is the 4281st most frequent Catalan word.
foren
"Foren" means "they were" or "they went" (past tense of "ser" or "anar").
In this sentence, 'foren' is used as the past tense form of the verb 'ser' (to be) in Catalan in its formal or literary form. It is equivalent to 'were' in English.
Els pobles foren unificats sota el mateix regne al segle XVIII.
The villages were unified under the same kingdom in the 18th century.
Here, 'foren' serves as the past tense of 'ser' in the passive voice structure to denote an action being performed (houses being built) in the formal register.
Les cases que foren construïdes prop del riu encara són habitades.
The houses that were built near the river are still inhabited.
In this instance, 'foren' indicates a past passive construction, showing that the action of reviewing was performed on the documents, in a literary context.