When in Doubt
When in doubt of exactly when a church was dedicated, then do it on October 22. That is, if you belong to the family of the Order of Preachers. (Dominican Family) When the actual date of the dedication of a church is unknown, the Dominicans celebrate its anniversary, today, October 22, the day on which the Dominican church at Toulouse was dedicated in 1385. This church which was one of the most famous of the Dominican churches in the early days of the Order was designated by Pope Urban V, in 1328, as the resting place for the remains of Saint Thomas Aquinas. The Mass is celebrated as a Solemnity.
* h/t http://daveys2france.blogspot.com/2010/01/toulouse-church-where-thomas-aquinas-is.html