The first is the religious order The Knights of the Cross with the Red Star which can trace it's origins back to 1233 and is situated by the Charles Bridge. The cross can be seen on the building from the bridge and the river.
It is also to be seen within the building in the floor tiles.
The other order is situated on the other side of the river. The Order of Malta ipalso has origins in Prague in the 12th Century. Their star can been seen here depicted on the Church of Our Lady beneath the Chain of the End of the Bridge (quite a mouth full for the name of a church).