This is the 11731st most frequent French word.
signées
"Signées" means "signed" in English.
In this sentence, 'signées' is used in its participial form, describing the letters having been signed.
Les lettres étaient signées par le directeur.
The letters were signed by the director.
Here, 'signées' modifies 'accords' and indicates that the agreements were signed prior to enabling peace.
Les accords signées ont permis d'établir la paix.
The signed agreements enabled the establishment of peace.
'Signées' is used attributively within the descriptive clause, specifying that all paintings have signatures.