The church of St Mary and Holy Cross served the Parish of Seton until 1580, when the Parish was joined with Tranent. The nave was demolished soon afterwards but the rest of the church was retained as the burial place of the Seton family. The choir and sacristy were begun by the first Lord Seton soon after 1470 and continued by his successors. In 1492 the second Lord Seton founded a college of six Priests, led by a Provost to say prayers for the souls of the family. Lady Jane Seton, widow of the third Lord, added the trancepts and tower.