In Russia, there was no spetsialnyh military monastic orders, as in Europe. Military service, as well as other "secular" profession were not allowed to the monks. But the majority of the monastery is a fortress. And if the enemy attacked, the defending fortress everyone who was there at that time. Including the monks were not idle during this time.
Besides, some monks were soldiers before the vows.
But to participate in military operations outside the monastery - is an exceptional event, for which permission was required esteemed bishop. In the chronicles known only one such case in which the front of the battle of Kulikovo two monks were sent into battle against the Mongols. Both were known before the adoption of vows and mighty warriors.
The participation of the monks in the defense of the fortress - monastery has many messages in the annals.
https://en.wikipedia.org/wiki/Solovetsk ... y_Uprising https://en.wikipedia.org/wiki/Siege_of_Jasna_G%C3%B3ra Unfortunately, there are many "scientific" books written dreamers. There you can read about Shao Linea in Russia, but it is - a lie.
So Red box set quite true, but the situation in the fortress, the monks were forced to defend themselves.
Now in Russia there are several priests who practice martial arts, but mainly the type of Aikido, initially a defensive struggle.