The official Church feast day for St. John Baptist de la Salle is April 7 (the date of his death). But because that day is oftentimes during Lent, Lasallians also celebrate his feast on May 15 which is today. (many religious orders have more than one feast for their founder). The Christian Brothers of course founded Trinity High School in 1970 as well as our predecessor schools and we are in talks about reaffiliating with them.
I had the honor of staying at the Christian Brother's motherhouse back in February during my visit to Rome. The skull of St. John Baptist de la Salle is in the chapel there and there is a nice statue of him on the grounds. I have posted pictures of these below.
Happy Feast Day!