Theophilus, when referred to in Bible, is the name of the person to whom the Gospel of Luke and Acts of Apostles is addressed. It can be considered as a Honorary title and the literal meaning of Theophilus when translated from Greek is Beloved of God or Friend of God. For reference and details see the link below: en.wikipedia.org
He was called Peter because it means 'Rock' and in the verse Matthew 16 :13 - 19 it states that: "I shall name you peter, this means rock. And upon this rock I will build my church." Jesus says. This shows that Jesus had great faith in this fisherman. And so their relationship begins to build.
Simon basically is an apostle of Jesus, better known as Saint Peter, Simon Ben Jonah, Cephas or Kepha. The initial name Simon or Simeon was one of the Twelve Apostles who Jesus selected from his original disciples.
His life is significantly marked in the New Testament Gospel as well as in the Acts of the Apostles, Peter who was a Galilean fisherman, was invited by Jesus to become his student. Above all the other followers or disciples, Peter was allocated a leadership role by Jesus.
The olden Christian Churches, like the Roman Catholic Church, Eastern Orthodox Church and the Oriental Orthodox Church, take Simon Peter as a saint, and the primary Bishop of Rome. The Roman Martyrlogy has set the date of 29th June as feast day of Peter and Paul.
