Rome’s earliest churches date from the 4th century, built by the Emperor Constantine; the most notable of the many churches that he commissioned is the Basilica di San Giovanni in Laterano. Reformed into its present shape in the 5th century, it was the model on which many subsequent basilicas were based. Other showstoppers of the period include the Basilica di Santa Maria in Trastevere and the Basilica di Santa Maria Maggiore, though they have been much altered since. A second wave of church-building hit Rome in the period between the 8th and 12th centuries, and the Renaissance period added still more architectural masterpieces. The architectural period that most shaped Rome’s churches, however, was the Baroque, whose opulent style mirrored the splendour, power and fury of the Counter-Reformation.