The decree from the Holy See officially erecting St. Thomas Aquinas Senior Seminary is dated 25th January 1963. In the same decree the Order of Preachers (Dominican Friars) were appointed to run the seminary. It is worth noting that the approval from the Vatican was for the erection of a “Regional Seminary.” Thus, the seminary was not limited to offering theological studies but all studies necessary for priestly formation. As a matter of fact the institution started by offering both philosophy and theology and it was not until later on that these disciplines were separated and offered on different campuses.
The first tonsure at St. Thomas Aquinas was conferred on the 8th of September 1965 to the pioneer class by Archbishop Guido Del Mestri, the Apostolic Delegate to East Africa. The first seminarians to receive the tonsure at St. Thomas were John Mutiso (Archdiocese of Nairobi), John Onkanga (Diocese of Kisii), Delphin Mugo (Archdiocese of Nyeri), Gabriel Njeru and Eleutherio Kiraithe (Diocese of Meru), Agapitus Muse, Cosmas Luyakha Khanyerere, Matthew Onyango, John Kwanga and Zacchaeus Okoth (Archdiocese of Kisumu).
In its sixth year of existence the seminary, on the 2nd of June 1968, it got its first deacons through the hands of His Eminence Maurice Michael Cardinal Otunga, of happy memory, who at that time was the Bishop of the Diocese of Kisii. The new deacons were John Mutiso (Archdiocese of Nairobi), John Onkanga (Diocese of Kisii), John K. Mak’Opiyo, Cosmas Luyakha Khanyerere, Agapitus Muse and Zacchaeus Okoth (Archdiocese of Kisumu), Gabriel Njeru (Diocese of Meru) and Delphin Mugo (Archdiocese of Nyeri).
Over 1,000 graduates of St. Thomas have been ordained priests and are working in various parts of the world. Of these five have gone on to become Archbishops and twenty have been ordained Bishops in Kenya.
To encourage the seminarians to be souls of prayer, the timetable at St. Thomas provides ample time for norms of piety. These norms include: daily adoration at 6.am, daily Mass, recital of the Divine Office, visits to the Blessed Sacrament, Holy Rosary, and spiritual reading. The formators are always on hand for spiritual direction and there are priests to listen to the confessions of the seminarians. Finally there are monthly recollections and annual retreats which offer the candidates for priesthood with an opportunity to reflect more deeply on their progress both in the spiritual life and in their vocation to the priesthood.