There are four areas of frescos. Some are more damaged by moisture and time than others. Visits to the Cripta are by reservation, which isn’t that difficult but speaking Italian helps. Contact the Ugento Archeological Museum a day before you would like to see the wall paintings.
(Records indicate human presence in the surrounding area from at least the fourth century B.C. Cripta del Crocefisso is located on the Via Sallentina, a route of the Messapian and Roman ages that connected Otranto to Taranto.)