James the Son of Zebedee, a.k.a.: James the older brother of John the Apostle, or James the Greater, or James the Elder
Note that “the Greater” means older or taller , rather than more important.

James the Greater is the author of the New Testament Book of James. Saint James the brother of John is one of the four fisherman chosen and invested (ordained, see Mark 3:14) by Jesus to be one of His disciples, “his fishers of men” (see Mark 1:16-20), and he is also one of the twelve apostles chosen and invested by Jesus.
James was one of only three apostles whom Jesus selected to bear witness to his Transfiguration (with Simon (Peter) and Jame’s Brother John).
James was known for being impetuous and having a fiery temper. Mark 3:17 says: “And James the son of Zebedee, and John the brother of James; and He [Jesus] surnamed them Boanerges, which is, The sons of thunder“. James and John (or, in another tradition, their mother) asked Jesus to grant them seats on his right and left in his glory. Jesus rebuked them, and the other apostles were annoyed with them. James and his brother John were also the ones who wanted to call down fire on a Samaritan town, but were again rebuked by Jesus.
About A.D. 44 James was martyred. Acts 12:1-2 states “Now about that time Herod the King [Herod Agrippa, the grandson of Herod “the Great”; 11B.C. – A.D. 44] stretched out his hand to harass some of the church. Then he killed James the brother of John with the sword”. James the Elder is thus believed to have been the first of the Apostles martyred for his faith.

James is the patron Saint of Spain. According to the 12th-century Historia Compostelana which contained the legend of St. James, after the crucifixion, resurrection and ascension of Christ, James traveled to Spain and evangelized those on the Iberian peninsula. He later returned to Jerusalem where he was martyred. After his martyrdom in Jerusalem James’ body was miraculously transported by angels to northern Spain where his body was interned (buried) at Santiago de Compostela. In the 9th century, this legend formed the basis for the pilgrimage route that began to be established, and a shrine dedicated to Saint James at Santiago de Compostela, was built in Galicia, Spain. The Shine became the most travel and most famous pilgrimage site in the Christian world. The Way of St. James is a trio of routes that cross Western Europe and arrive at Santiago through Northern Spain. Eventually James became the patron saint of Spain.
An even later legend states that he miraculously appeared to fight for the Christian army during the battle of Clavijo (a mythical battle in the Spanish war to expel the Moors from Spain), and was henceforth called Santiago Matamoros (Saint James the Moor-slayer).