Can you use the Diurnal with the modern or pre-1960 Roman calendars? A guide to August, Pt 1

There has been some discussion in a number of places recently on using the modern sanctoral Roman calendar (or some variants thereof) in conjunction with the Monastic Diurnal, so I thought I might provide some notes on this topic, as well as the related topic of the pre-1960 Benedictine or Roman calendars, using the month of August as an example.

The Office and the Mass

In essence, the problem is this: in an ideal world, the Office of the day should align with the Mass you attend.  

The Office and the Mass are supposed to reinforce each other, and on saints feasts, for example, at a minimum they will usually share the same collect, and the 'proper' texts (whether from the Common of the relevant type of saint, and/or specific to the feast) typically reflect similar themes. 

But there will always be at least some differences.

You might turn up to daily Mass and find that a Requiem Mass is being said that day for example, or perhaps a votive Mass, instead of the Mass of the day, neither of which have any necessary link to the Office required to be said that day (the Office of the Dead being entirely optional).

Moreover, for many feasts, the impact on the Office at the day hours at least (Matins is a different story, since it will typically contain at least one substantive reading on the saint of the day) is relatively minor.

So its arguably not a big deal if you say the Office of a feast, but the Mass you attend doesn't celebrate it, or vice versa.

Differing calendars

It is also important to be aware that unless you attend daily Mass in a monastery following the 1960 calendar, discrepancies between the calendars of the Office as set out in the Monastic Diurnal and the Mass you attend are inevitable. 

If you attend a Roman Extraordinary Form Mass, you will find it includes several feasts either not included in the Diurnal calendar at all, or in some cases, said on different days. 

And the differences are even greater with the Roman 2025 calendar, which moves many feasts to different days, and adds several new ones.

Possible approaches

Accordingly, it is certainly possible to simply use the Diurnal (or Breviary) and ignore any differences in the feasts celebrated in the Mass that you attend.

If you do want to align calendars between the Mass you attend and the Office that you say however, it really isn't actually that hard to do, and doing so is arguably perfectly consistent with liturgical law.  There are a couple of options you can follow.

Using the modern sanctoral calendar

The first option, which I understand is followed by the Solesmes Congregation traditional monasteries, is to move the sanctoral calendar around so that feasts are said on the same date as they are in current Roman calendar.  

In essence, when the Benedictine Confederation effectively deregulated control of the Office to individual monasteries and/or forced certain monasteries to use something other than the 1962 Mass, it required monasteries to use the Roman sanctoral calendar as it then stood together with a list of supplemental feasts for the Confederation. So, particularly if you are an oblate of one of those monasteries and attend a Novus Ordo Mass, you should ideally say the Office of the saint of the day in the 2025 calendar, not the monastic 1960 one.

Clear Creek Monastery has actually published two supplements, one for the Antiphonale (day hours) and one for the Night Office, available through Lulu, to assist this (it is worth noting though, that these books use older terminology for feast levels, and their calendar of saints does not always entirely align with the Roman 2025 one).

But you can get most of the way yourself without these if necessary.

In August, for example, as the table below shows, if you compare the current Roman calendar with the 1960 Benedictine one, there are ten feasts that are said on exactly the same day (highlighted in yellow), so you can just follow the Diurnal for them.

There are also a further five feasts celebrated on a different date (highlighted in green), so simply a matter of looking the saints name up in the index of saints names in the Diurnal, and using the texts on the appropriate date.

The 2025 calendar also contains several saints canonised since 1960 (highlighted in blue), most notably SS Peter Eymard (canonised 1962); St Teresa Benedicta (canonised 1998); and St Maximilian Kolbe (canonised 1982).  In these cases, the decree Cum Sanctissima gave permission for their Offices (and Mass) to be said with the 1962 books as Class III feasts.  Simply use the Common for the relevant type of saint - confessor for St Peter Eymard, Virgin martyr for St Teresa Benedicta and so forth.

That then leaves you with nine saints whose feasts were included in the 1962 Roman (EF) calendar, but not in the 1960 monastic one (although in a few cases they were in the 1953 and earlier calendars), highlighted in orange.  In some, but by no means all, cases the Solesmes Congregation has included these and you can find the necessary texts in the Supplements, use the Commons, or use an EF 1962 Office book to provide the necessary texts.

Adding feasts to the 1960 calendar

The other (and rather simpler) approach you can take is, consistent with Cum Sanctissima, simply to add any 'missing' feasts - newer or older (see purple highlighted) to the calendar set out in the Diurnal, and use normal principles where clashes occur.  If you want to say the Office of the Vigil of  St Lawrence, for example, you could mark the feast of St Teresa Benedicta as a commemoration.  It is not a perfect solution, but will get you 90% of the way...

DAY	ROMAN 2025	Benedictine 1960	Benedictine 1953
1	St Alphonsus Liguori, M, MD [210] (1960: Aug 2)	The Holy Maccabees, Memorial	St Peter in Chains; coms of St Paul, Maccabees
2	St Eusebius of Vercelli, Opt M (Roman 1962, commemoration; Benedictine 1953, Aug 14)	St Alphonsus Liguori, Memorial	St Alphonsus Liguori; St Stephen
2	St Peter Julian Eymard, opt m
3	St Dominic, MD [211] (1960: Aug 4)
3	St Germanus of Auxerre (Wales)
4	St John Vianney M (Roman 1962: Aug 8)	St Dominic, Cl 3	St Dominic
5	The Dedication of the Basilica of St Mary Major, MD [211 – Our Lady of the Snow]	Dedication of Our Lady of the Snows, Memorial	Dedication of Our Lady of the Snows
6	The Transfiguration of the Lord, MD [212	The Transfiguration of the Lord, Cl 2	The Transfiguration of the Lord; SS Sixtus II, Felicissimus and Agapitus (1960 – Aug 7)
7	SS Sixtus II & companions, MD [219]	SS Sixtus II, Felicissimus and Agapitus, Memorial	St Cajetan
8	St Cajetan (Roman 1962: Aug 7)	St Cyriacus	St Cyriacus
8	St Mary of the Cross, F (Aust)
9	St Teresa Benedicta of the Cross	Vigil of St Lawrence, Cl 3	Vigil
10	St Lawrence, F, MD [220]	St Lawrence, Cl 2	St Lawrence
11	St Clare, M, MD [228] (1960: Aug 12)	St Tibertius, Memorial	St Tibertius and Susannah
12	St Jane Frances de Chantal (1960 Roman: Aug 21)	St Clare	St Clare
13	SS Pontian and Hippolytus, MD [228]	SS Pontian and Hippolytus	SS Pontian and Hippolytus
	St Fachtna (Ireland)
	St Radegunde (France)
14	St Maximilian Kolbe, M	Vigil of the Assumption, cl 2	Vigil; St Eusebius
15	Assumption of the BVM, S. MD [230]	Assumption of the BVM	Assumption of the BVM
16	St Stephen of Hungary (Roman 1962: Sept 1)		Octave of Assumption
17			Octave, St Lawrence
18		St Agapitus, Memorial	Octave; St Agapitus
19	St John Eudes (Roman 1962)		Octave
	St Bernard Ptolemy
20	St Bernard, M, MD [245]	St Bernard	Octave; St Bernard
21	St Pius X, M, MD [258] (1960: Sept 3)	St Bernard Ptolemy, Memorial	Octave; St Bernard Ptolemy
22	The Queenship of the Blessed Virgin Mary, M (Roman 1962: May 31)	St Timothy, Memorial	Octave day, SS Timothy and Symphorianus
23	St Rose of Lima (Roman 1962: Aug 30)		Vigil
24	St Bartholomew, F, MD [250]	St Batholomew	St Batholomew
25	St Joseph Calasanz (Roman 1962 : Aug 27)
	St Louis, MD 42**
26	St Caesarius of Arles, (France)
27	St Monica, M (Roman 1962: May 4)
28	St Augustine, M, MD [251]	St Augustine, cl 3	St Augustine
29	The Passion of Saint John the Baptist, M, MD [252 – The Beheading of St John the Baptist]	The Beheading of John the Baptist, Cl 3	Beheading of John the Baptist
30	SS Margaret Clitherow Anne Line and Margaret Ward, martyrs (England)	SS Felix and Adauctus, Memorial	SS Felix and Adauctus
31	St Aidan (England and Ireland)

(Key: S-Solemnity, broadly equivalent to Class I; F=Feast/Class II; M/OptM = Memorial or Optional Memorial/Class III).

In the next post, I'll provide a few more notes on how to say some of these additional Offices, and I'll consider doing a version of this exercise for all months and providing page numbers and or references to the relevant Common if there is enough interest.  

I understand, though, the Benedictine Confederation are actually considering a revised calendar at the moment, so it may be worth waiting a while to see what emerges...