Complex sentence: The creation of the order is an instance within a larger fashion of founding chivalric orders during the 14th and early 15th centuries, not infrequently dedicated to organizing "crusades", especially after the disaster of the battle of Nicopolis (1396).
Split into simpler sentences: The creation of the order was an instance within a larger fashion of founding chivalric orders during the 14th and early 15th centuries. Not infrequently dedicated to organizing "crusades", especially after the disaster of the battle of Nicopolis (1396).