While modern day Spain is known as singular country governed under a King and a Prime Minister, it has not always been like that, particularly in the 15th century. What we call Spain today was divided into many different kingdoms centuries ago, the most powerful being the kingdom of Castile. In the year 1474, Castile’s King, Henry IV passed away leaving the throne unoccupied and open to be seized. While many thought the most obvious and rightful successor to the throne was Henry’s daughter, Joanna la Beltraneja, others had differing opinions as to who should rule Castile. Joanna’s opponent in the fight for the throne was Henry’s half-sister, Isabella, who was ultimately successful in taking the throne of Castile. However simple and succinct this resolution may sound, it was not an effortless road for neither Isabella nor Joanna as this struggle for power resulted in a war that lasted for four years known as the War of the Castilian Succession. Wars are often fought for many noble reasons such as resistance and freedom, however this war was unabashedly a conflict in the name of power and influence. In this paper I will explore what lead to, what conspired during, and what ended the war.…