NoDictionaries   Text notes for  
... est: Agrippina et Acerronia eminentibus lecti parietibus ac forte...

eminentibus...validioribus...cederent: abl. abs., the walls/posters of the bed in which Aggripina was lying were protruding ("eminentibus") and by chance strong enough ("validioribus," lit., stronger) than that they should yield ("cederent') to the weight [of the falling lead].