Breakdown of La emperatriz firmó el tratado, el cual fue rechazado por el rey.
ser
to be
firmar
to sign
por
for / by / through / in (during a part of the day)
el rey
the king
Questions & Answers about La emperatriz firmó el tratado, el cual fue rechazado por el rey.
Could I just use que instead of el cual in this sentence?
Yes, you can. In non-defining relative clauses (the ones separated by commas that add extra, non-essential information), que is very common. However, using el cual elevates the register, making the sentence sound more formal, written, or literary.
How do we know el cual refers to the treaty and not the empress?
The relative pronoun el cual must agree in gender and number with the noun it refers back to (its antecedent). Because it is masculine singular, it can only refer to el tratado. If the relative clause were about la emperatriz, you would have to use la cual.
Why does this sentence use fue rechazado instead of estaba rechazado?
This is an action being done to the treaty by the king, so we use the true passive voice with the verb ser (here in the preterite as fue) plus the past participle. If you used estar instead, it would focus on describing the resulting state or condition of the treaty, rather than the actual event of the king rejecting it.
The feminine of the emperor is la emperatriz. Are there many words that end in -triz?