Christianity, one of the world's largest religions, has a profound impact on the lives of over 2.1 billion people globally. Its rich history, rooted in the teachings of Jesus Christ, is intertwined with centuries of theological development, religious movements, and cultural influence. 

Origin:

Christianity traces its roots to the life and teachings of Jesus Christ, born in Bethlehem around 4 BC. Regarded by his followers as having superhuman abilities, Jesus embarked on a mission of preaching and traveling to various towns. His growing popularity and his message of salvation posed a threat to some Jewish priests, leading to a conspiracy against him, culminating in his crucifixion. However, the story takes a miraculous turn, as Jesus is believed to have been resurrected on the third day and subsequently ascended to heaven after 40 days on Earth.

The events surrounding Jesus' birth and the prophecies of the Old Testament foreshadowing the arrival of the Son of God to atone for humanity's sins played a pivotal role in shaping the foundation of Christianity. The followers of Jesus established a new faith called Christianity, with its adherents known as Christians.

Significance of Christianity:

Christianity, founded in Jerusalem by Jesus Christ, quickly gained followers after his resurrection. It later became the official religion of the Roman Empire and witnessed rapid growth. The city of Vatican became the centre of Roman Catholic Christianity. Over time, various reform movements within Christianity emerged, leading to the formation of different sects like Protestants, Methodists, and others.

The Holy Bible, composed of Hebrew, Aramaic, Greek, and English texts dating from 9 BC to 1 AD, is the sacred book of Christians. It comprises two main sections: 

• The Old Testament, shared with Judaism
• The New Testament, which focuses on Jesus Christ's life and teachings, central to Christian faith.

Tenets of Christianity:

Christianity's core tenets include:

1. Monotheism: Christians believe in the existence of one God who created the Universe.
2. Messengers and Messiahs: When necessary, God sends messengers or messiahs to assist humanity. Jesus is a central figure as a messenger sent to guide people and act as their "savior."
3. Holy Trinity: Christians worship the Holy Trinity, which includes God the Father, Jesus the Son, and the Holy Spirit, believed to be God's presence on Earth after Jesus' death.
4. The Bible: The Bible serves as the holy scripture of Christians, comprising the Old and New Testaments.
5. Sacraments: Christians participate in various sacraments, including baptism, a significant initiation rite, and the Eucharist, symbolizing unity with God through the sharing of bread and wine.
6. Apostles: Jesus selected 12 apostles to spread his teachings and guide people. These apostles, including Peter, James, and John, played a crucial role in the early Christian community.

Sects in Christianity:

The history of Christianity is marked by several divisions and reforms, leading to the emergence of various sects. After the conversion of Emperor Constantine in 313 AD, Christianity became the official religion of the Roman Empire. The religion was initially known as Catholic or universal, with the Roman Pope as its leader. 

By 1054 AD, the Church formally split into the Eastern Orthodox and Western Roman Catholic schools. The 15th century witnessed challenges to the Pope's authority, and in the 16th century, Martin Luther spearheaded reforms in the form of Protestantism, which emphasized the Bible as the sole authority.

Christianity in India:

• India has a rich history of Christian presence, dating back to legendary accounts of St. Thomas the Apostle's arrival on the Malabar Coast in 52 AD. Some accounts claim that St. Bartholomew was the first missionary in India. 
• The Portuguese discovery of a maritime passage between India and Europe in 1498 led to cultural exchanges between the two regions. The Portuguese also made attempts to convert Mughal Emperors Akbar and Jahangir to Christianity. 
• Christian scholars engaged in religious debates in the Ibadatkhana, established by Akbar.
• Christianity expanded further during the British colonial period when various missionary groups arrived in India. Their efforts included not only religious conversions but also the provision of modern education and healthcare to those who embraced Christianity. 
• Presently, a variety of smaller denominations, including the Syrian Christians of Kerala and Protestant groups, contribute to the diverse Christian landscape in India. There are 23 dioceses in India, with 11 located in Kerala.

Christianity stands as the world's most widely practiced religion, with a global following of over 2.1 billion adherents. In India, Christianity is the third-largest religion after Hinduism and Islam. It has significantly contributed to the nation's cultural and religious tapestry and remains an integral part of India's spiritual and social landscape. Over the centuries, Christianity has evolved, with a rich history of reformations, theological development, and cultural influence.