If you don't know already, Saint Antiouchus' Die always rolls a three. This means that if you have a full set of them, you can just keep rolling forever and are guaranteed to win.

You can get a full set of these nearly at the start of the game. In Troskowitz,there's a dice table by the inn where you can play dice with a guy just named "Hired Hand". He has one of these die.

Unfortunately, it doesn't seem like you can pickpocket it off of him. You can, however, break into the inn at night and get it from him that way. He sleeps in the room above the pantry in the double bed, next to Innkeeper Betty. If you try to knock him out here, you'll wake Innkeeper Betty and she'll run to get the guards. So instead, you can wake him by throwing a rock on his side of the bed. Let him see you (It's only blue trespassing, so not immediately a crime) and make him escort you off of the property. I recommend making him go left out of the pantry and then left again out into the field to avoid any guards. Once he turns to go back to bed, choke him out and rob his unconscious body.

The doors to the inn are locked at night, so you do need either a lockpick or a set of keys to get in. You can either pickpocket the keys off of this guy during the day or you can lockpick your way in once and steal some keys off of him the first time you get the die.

It takes about 2-3 days for him to get a new die, but you can repeat this until you have a full set.

In the meantime, you can buy one Odd Die each day from the innkeeper at Zhelejov Wagoner's Inn. This has an increased chance to get any odd number (although not guaranteed) and is a good fit to supplement Antiochus's Die until you can get a full set.