Christians have the responsibility to go out and tell other persons about the Gospel and how God formed a plan of salvation, which was put into force when the Lord Jesus Christ died on the cross and was resurrected the third day. God has the responsibility to draw that person to Himself or not to draw that person to Himself. He is God and He makes the decisions:
John 6:65New International Version (NIV)
65 He went on to say, "This is why I told you that no one can come to me unless the Father has enabled them."
Trying to convert them into Christianity
If you are referring to religions that others attempted to force on the Jews, they were Christianity, Islam, and many pagan religions.
Tradition holds that Cecilia converted her husband, Valerian, and his brother Tibertius to Christianity. There may have been others.
to convert many people to Christianity
Vladimir I ordered his subjects to convert to Orthodox Christianity.
Christians strongly believe that their religion is the one true religion. Some Christians also believe that they have a duty to convert followers of all other religions, to Christianity. For some, there may even be a sense that it is in some way irrational for others not to convert readily to Christianity, when told what Christians believe. Also, it is a requirement among certain minor Christian sects and denominations for young adults to spend up to two years attempting to convert others.
Constantine
Absolutely not.
Christianity.
No.
In the summer of 386 Augustine converted to Christianity.
Constatine