Or they gave that service in exchange of a landholding (a fief) - but these were not given to mere serfs, only to trusted, already quite privileged freemen.
या भनौँ यो यति स्वाभाविक हुन्छ कि कसैले यसमाथि प्रश्न उठाउनु जायज नै ठान्दैन वा यसलाई निरपेक्ष ठान्छ ।