Complex sentence: In 1713, the War of the Spanish Succession ended indecisively although the French forces and allies (of which Spain was one) were in complete control of Spain itself, they failed to retake the Spanish Crown's other European territories.
Split into simpler sentences: In 1713, the War of the Spanish Succession ended indecisively. Although the French forces and allies (of which Spain was one) were in complete control of Spain itself, they failed to retake the Spanish Crown's other European territories.