Constantine married or otherwise began his relationship with Minervina in 303.
In 307 he set aside Minervina and married Fausta. 
Constantine's relationship with Minervina is uncertain. If theirs was a real marriage, a divorce would have been required before his second marriage, but no record exists of one. On the other hand, if the relationship had been illegitimate, Constantine is unlikely to have treated their son Crispus as well as he did. One suggestion is that Minervina might already have been dead by 308. 
After setting Minerva aside in 307, he married Fausta (Maxima Fausta Augusta). 
In 326 Constantine had Fausta killed in an overheated bath. 
313 Edict of Milan
In February 313 the Edict of Milan was signed by Constantine and co-emperor Valerius Licinius. The Edict granted religious freedom for the Roman Empire. Posted in Nicomedia.
325 Council of Nicea
In 325, in a effort to restore religious peace, Constantine called the religious leaders of Christendom to meet at the First Council of Nicea and settle the controversy between the Christian theologians Arius and Athanasius, both of Alexandria, Egypt, primarily over the nature of God and Jesus.
Constantine was baptized a Christian on his deathbed, 22 May 0337 in Constantinople by Eusebius of Nicomedia. 
He was buried in the Church of the Holy Apostles, Constantinople 
Children by his first marriage to Minervina
Crispus Presumably born between Minervina's marriage in 303 and her dismissal in 307.
Between 15 May and 17 June 326, Constantine had Crispus seized and poisoned to death while he was in Croatia. 
Constantius II, married Faustina. Their daughter Constantia married Gratian, emperor 36t7-383.  Constantius killed his nephews Dalmatius and Hannibalianus to keep them from contending for the throne.
A bogus pedigree initiated by Henry of Huntingdon inserts St. Helen (Empress of Rome), as a daughter to make Coel the father of Constantius Chlorus ... The false pedigree was then passed on by Geoffrey of Monmouth:
↑ Galerius, created two Caesars: MAXIMIN, appointed over the east; and SEVERUS, Italy. After Constantius died, CONSTANTINE became emperor in Britain, and succeeded his father... while praetorian guards in Rome, declared MAXENTIUS, emperor.