Etenim cum expedita manu clam in Masoviam ingressi, Ioannem ducem Cirnensium nihil hostile suspicantem, in praedio quodam, sive apud Zlotoriam arcem, quam tunc ligneam aedificabat, cepere, et equo impositum, ac subter alvum equi pedes indigne colligatum, arce incensa secum abduxere etc...
...they put him on a horse, and dishonorably tied him below the horse's belly with respect to his feet??
is pedes an accusative of respect or something here?