The present church was built in the time of Pope Honorius III (1216–1227), and altered by T. de Marchis in 1750 on the orders of Angelo Maria Quirini. After 1846, when the Somaschi Fathers were installed here, further alterations have been carried out.
The church has beautiful Cosmatesque work on the floor, doorway and the two small columns of the choir. On one of the columns, there is an inscription naming the artists as Laurentius and stating that there were 19 columns. The fathers in the church say that the 17 missing columns were carried off by Napoleon. A statue of St. Alexis stands above an altar by the door. It shows him in pilgrim's clothes, clasping the letter which revealed his identity after death. The statue is by Andrea Bergondi, and was made in the late 18th century. Parts of the staircase that the saint lived beneath are preserved here. The crypt is from the 10th or 13th century. It's closed to the public most of the year, but at Christmas a crib, one of the most popular in Rome, is set up here. The crypt is in the Romanesque style; it is the only crypt in that style in Rome. Relics said to be of St. Thomas Becket of Canterbury are preserved here. (Text based on the Churches of Rome Wikia).