Explanation of why there are two feast days for the Chair of St. Peter...
St. Francis de Sales - Feast Day is January 29th
St. John Chrysostom - Feast Day is January 27th
St. Ambrose - Feast Day is December 7th
St. Peter Chrysologus - Feast Day is December 4th
Saint Margaret Mary Alacoque - Feast Day is October 17th
St. Teresa of Avila - Feast Day is October 15th
St. Jerome - Feast Day is September 30th
A short of list of MUST knows...
St. Ignatius of Loyola - Feast Day is July 31st
St. Anne - Feast Day is July 26th