Relics in the Altar

Altars in Catholic Churches have what are called"Altar Stones." The relics of at least two saints, at least one of which had to be a martyr, were inserted in a cavity in the altar which was then sealed -- this was meant to recall the use of martyrs' tombs as places of Eucharistic celebration during the persecutions of the Church in the Roman Empire in the first through third centuries. A typical misunderstanding of Catholics is that the relics of the saint in the altar stone are the relics of the patron saint of the parish church. Thus, people might expect that the relics of St. Leonard are in our altar stone. That is not the case. Altar stones usually contain the relics of early Christian martyrs.
The documents attached to our church altar stone name the relics as those of Saints Laetus and Modestinus. Who are they?
St. Laetus died in 553. He is a priest honored in Orleans, France. His relics are enshrined in St. Lie. His feast day is November 5.
There are 8 Saints “Modestus.” Some of them are listed here.
1. Feastday: February 12. He is venerated as the patron saint of Cartagena in Spain. He was martyred at Carthage about 160.
2. Feastday: February 12. He was a Martyr who died in Alexandria, Egypt. The date of martyrdom is unknown. Nothing is known about him.
3. Feastday: February 12. He is a deacon, said to have been a native of Sardinia. He was martyred under Emperor Diocletian about 304.
4. Feastday: February 24. He was bishop of Trier during the period of Frankish rule over the area from 486. His relics are enshrined in St. Matthias, Trier. Modestus suffered much during that difficult era. d.489.
5. Feastday: February 5. He was a Benedictine bishop, trained by St. Virgilius in Salzburg, Austria. He became regionary bishop of Carinthia, modern Austria, and evangelized the region. He died in 722.