In 1035 the Castilian county became a kingdom, under the reign of Fernando I. Shortly after, Fernando led a coalition of Castile and Navarre in a war against Leon in which the king of Leon was killed. As the slain king had no offspring, Fernando, brother-in-law to the dead king, claimed the crown of Leon. This brought about the first union of the two kingdoms, Leon and Castile Learning Spanish Like Crazy review. They were partitioned again in 1195 and finally re-united in 1230. Spanish is a popular language to study as a second language because it is relatively easy to learn and it opens up exciting new vistas to those who make the effort to learn it.