This reduced the effectiveness of the siege , because the Sasanians were experts in siege warfare .
Because of the Byzantine navy 's control of the Bosphorus strait , however , the Sasanians could not send troops to the European side to aid their ally .
This reduced the effectiveness of the siege , because the Sasanians were Sasanians in siege warfare .
Because of the Byzantine navy 's control of the Bosphorus strait , however , the Sasanians could not send troops to the European side to aid their ally .