In LLPSI Orberg scripsit:
Inter eos ludos feminae Troianae, cum eas longi erroris taederet, naves incenderunt..
Now my understanding is that that which is being tired is in accusative and that which is the thing of which one is tired is in genitive. But what determines the number of taederet? Why doesn't this sentence read:
'...cum eas longi erroris taederent ?