Three first order markers emerge in the Portuguese past century history: 1910, 1928, and 1974; behind them loom the two World Wars and the Portuguese colonial wars of the 60's (Angola; Guinea-Bissau; Mozambique). On October 5, 1910 the monarchy was overthrown and a republican regime (1st Republic) was inaugurated. The sort of relationship reset by the new political power in respect of the Catholic Church may be said to have been dominantly adversarial. Separation between State and Church was established; a significant part of the then vast Church property was confiscated; and various legislative diplomas were promulgated, seriously curtailing traditional domains of non-church clergy activity, e.g. in primary and secondary level education.

At a still early stage, the republican governance was confronted – and directly affected via Portuguese African colonies – by the eruption of the First World War. Geopolitical reasons led the government to enter the war along with France and the United Kingdom, no matter the serious dissent that entailed in most varied national quarters. The end of the war, coming without the expected winners' financial aid to help smoothing out the incurred huge public debt, left the country in a dire economic situation. Powerless to come up with domestic solutions, the government was as well unable to quench generalized populace anger and the ensuing waves of violent social unrest. That led to a military coup on May 26, 1926.

The incoming military leadership from the very start called on a Coimbra University full professor of Public Finance, Antonio Salazar, for helping them to turn around national accounts. In 1933, buoyed by Italian and German precedents, Salazar imposed a climb down on the military leadership, rewrote the republican Constitution and set up an authoritarian regime, which was going to last until 1974 – though, from 1968, due to Salazar's incapacitation, power was transferred to one of his most distinguished followers, Marcello Caetano.

Salazar was a shrewd politician. Even being a deeply devout Catholic, he never allowed the Catholic Church to meddle in top political decisions. He restored some of the Church’s old prerogatives done away with in the course of the 1st Republic. To no surprise he was fully supportive of the traditional stand of the Catholic Church in respect of the rural, very low standard of living, exalting the virtues of «terrestrial» poverty – and belated, next life enjoyment of full accrued benefits. With the usual exception of a proportionally minute urban intelligentsia, the vast majority of the population was observing and subject to parish clergy oversight, not only in the spiritual domain but, to a vast extent, also in social endeavors at large.

As said, authoritarian rule came to an end in 1974. The April 25 military coup, which focused first and foremost on putting an end to the lingering, unwinnable colonial wars, instantly became a democratic revolution due to spontaneous full popular support. Four-plus decades on, the impact of this regime change (2nd Republic) on religious tendencies can be traced and interpreted.

The 1900 national census identified 99.9 % of self-proclaimed Catholics. One century later (2001), the corresponding figures became respectively 8.75 million and 84 %; adding up the respondents who declared some other affiliation, the result identified 87.1 % of the Portuguese  as 'followers' of a religious creed. In 2011 (latest national census), this latter figure became 84.9 %, due to an increase of self-declared «non-religious» persons: 6.8 % (or 615 332 individuals) against 3.9 % (342 987) ten years earlier.

More startling is the fact that from 1940 to 2001 the highest absolute value within the self-declared «non-religious» category was recorded precisely in 1940 (347 284), with a later absolute minimum in 1960 (147 774). A hint of what the «non-religious» self-classification really means can be found in studies carried out by the Portuguese Catholic University in 1999 and 2011. This latter inquiry placed the sum total of non-believers and believers-without-religion at 14.2 % of the valid inquest replies – by the way, a figure very much in line with Pew Research Center results for the world population (16 %). This sum total aggregates the following components: indifferent (3.2 %); agnostic (2.2 %); atheist (4.1 %); and believer without religion (4.6 %). This means that only 10 % saw themselves as non-religious.

The 2011 national census also assessed the «other religions» (3.9 % or 347 756 individuals), which were subdivided into the following: Orthodox Christians (0.63 %), Protestants (0.84 %), Other Christians (1.82 %) Jews (0.03 %), Muslims (0.23 %), and Other Non-Christians (0.32 %). By way of comparison, the above mentioned 2011 Portuguese Catholic University study provided the following data: Protestants/Evangelic (2.8 %), Jehovah’s Witnesses (1.5 %). Other Christians (1.6 %); and Non-Christian religions (0.8 %).

In a 2007 study on Catholic Europe, Arroyo Menéndez focused on the data-generated idea that Portuguese religiosity is essentially «traditional», inter alia characterized by a high degree of trust in the ecclesiastical institution, the latter being seen as a guarantor of 'moral order' and a secure provider of 'guidance principles'. For developing a feel on what such a statement may entail it is helpful to observe a series of statistics.

It is interesting to note that the number of weddings fell from 71.6 thousand in 1990 to less than half of it in 2014 (31.2 thousand). While in 1991 27.9 % of all weddings were non-Catholic, the corresponding figure for 2013 was 63.5 %. A closer examination shows that civil weddings evolved in a seesaw mode, reaching a maximum in 2007, while in 2014 they returned to essentially the same magnitude as in 1990. Catholic weddings, in turn, quantitatively declined in a monotonic way from the beginning to the end of the same period. In parallel, from 1990 to 2010 divorces both in Catholic and in civil marriages shot up at very close rates (respectively, factors of 1.95 and 2.05). From that year on, both kinds of divorce kept declining. Finally, the proportion of children born out of wedlock more than tripled from 1991 (15.6 %) to 2013 (47.6 %). 

Seemingly, two kinds of inference can be extracted from these data. The first one is that the Portuguese economic crisis (triggered by the 2008 international financial bubble burst) significantly discouraged marriage, with a corresponding impact on birth rates (from 112.8 thousand in 2001 to 82.8 thousand in 2013). The second (most encompassing) one is a clear indication that «traditional guidance principles» are no longer what they used to be. Catholicism may be overwhelmingly claimed by residents in Portugal as their religion, but in reality many do not abide by Catholic Church norms regarding the nuclear family fabric. Many self-proclaimed Catholics do make a distinction between Catholic doctrine and the institutional Catholic Church.  

One may go even further: when «intellectual» critics of Christian religions try to «denounce» what they there condemn from a humanistic standpoint, they mostly focus on despicable moves by the top hierarchy, clergy malpractice, errors and so on. Consequently, that sort of criticism ends up having minute following in the believer masses at large; this seems to be a consequence of the separation between doctrine and 'clergy' practice that believers have along the way incorporated into their personal belief systems. In this perspective, the multiplication of «legalized» creeds – full freedom of religion in Portugal was only instituted by the 2nd Republic – surely has been and will remain a mind-opening factor.

The above quoted sample statistical data also point to the fact that the very aggressive anti-clergy line of the 1st Republic’s political leadership did not have a lasting effect on the generation that reached maturity around the time of the Spanish Civil War/start of the Second World War. One might even hypothesize that the 1960 census minimum in the self-declared «non-religious» category was the consolidated effect, on one hand, of the forceful religious indoctrination practiced by the authoritarian political regime from 1933 on, and on the other hand of the promising economic perspectives the regime was offering at that time (beginning of the 60's) in terms of more employment and improved wages. This implies that even religious feelings can, at least in the short run, to some extent even in the medium run, be instrumental and manipulated — as was for example the case in Stalin's Soviet Union and Hitler's Third Reich.

Consequently, the above mentioned «tradition» argument is open to discussion. At least in the Western context, there seems to be no doubt that a rising standard of living tends to enhance individualism. In Portugal, the 2nd Republic achieved undeniable progress in quality. The index of infant mortality, set at 77.5 ‰ in 1960, dropped to 2.9 ‰ in 2013; male life expectancy rose from 60.7 years in 1960 to 77.2 in 2013, female from 66.4 to 83.0 years; illiteracy rates fell from 25.7 % in 1970 to 5.2 % in 2011; the annual flow of doctorates went from 60 in 1970 to 2.7 thousand in 2013; GDP per capita progressed from 3.5 thousand euros in 1960 to 16.7 thousand in 2011 (at 2011 constant prices). How, then, can we explain occurrences such as the constancy of afflux of Portuguese nationals to the Our Lady of Fatima Sanctuary ceremonies that take place every year, above all in the month of May, but also in August and in October? The 2008 Fatima Sanctuary Annual Report specifies as heads count just for mass attendance at the Sanctuary, 4.2 million persons in 2006, 4.9 million in 2007 and 4.2 million in 2008.

On the face of this evidence the conclusion this text extracts is that essentially quantitative methods – obviously supported by founding interpretative models – are not sufficient for fully explaining religious phenomena dynamics. It is undeniable that such methods are invaluable, and indispensable for shedding light into undercurrents that otherwise would remain undetectable. But, by the same token, the religious phenomenology is home to factors that transcend the modelling constraints inherent to such methods; reason why the science of religion ought to remain multidisciplinary in the fullest sense, and utterly open-minded.

Having decided not to involve Portugal in the Second World War, Salazar sought an agreement with the Holy See that could give him some sort of «assurance» – though he ended up caving in to impositions by both belligerent sides. With his weak negotiating hand he had no choice but to accept the Holy See diktat of including in the convention (Concordat), signed in May 1940, two provisions he was against: the legal inadmissibility of divorce in Catholic marriage and mandatory Catholic religion classes in State schools. The first provision was revoked by the 2nd Republic through a Protocol entering in force in 1976. The second one had to wait until a new Concordat was agreed in May 2004.

The latter dropped the clause as per article XX of the 1940 Concordat: «Church associations and organisations may freely establish and maintain their particular schools parallel to those of the State, subject, under the general law, to supervision and may, under the same terms [as State schools], be subsidised and accredited.» Furthermore, it put an end to mandatory Catholic religion classes, stipulating instead that (article 19, nº 2): «The enrollment in the teaching of Catholic religion and morals in non-higher public education establishments depends on a statement by the interested or his legal representative.» Nowadays, the Catholic Church is institutionally present in all segments of education, strictly subject to the overall regulatory regime.

In respect of Islam and Muslims there is no real issue. Many Muslim residents in Portugal are people who left mainly Mozambique, and to a smaller extent Guinea-Bissau, at the time of (or soon after) the independence of those former colonies. Accordingly, they were accepted by the Portuguese society at large simply as fellow citizens practicing a different creed. That atmosphere of mutual acceptance and respect may have favoured the June 2015 Agreement establishing in Portugal the Global Seat of Ismaili Imamat. The Shia Imami Ismaili Muslims are led by Aga Khan, the 49th hereditary Imam, who is said to be a direct descendant of the Prophet Muhammad through his cousin and son-in-law, Ali, and his wife Fatima, the Prophet’s daughter. In following Islam's ethical tradition the Ismaili Imamat leadership is concerned about the well-being of all Muslims but also sees it as its responsibility to help improve the quality of life of Muslims in their communities and in the societies in which they live, always from the standpoint of helping to build self-reliance. To that end, the Imamat acts inter alia through the Aga Khan Foundation and the Aga Khan Development Network (AKDN). Worldwide, AKDN is present in 24 countries, from Afghanistan to the USA, but only in three European countries (Portugal, Switzerland and the United Kingdom).

In brief, Portugal is a country where religion/secularism matters are dealt with essentially no commotion. Even divisive issues such as abortion or same gender marriage, though the object of conflicting views, are not the source of societal rifts. Thereto the Catholic Church appears to follow a line of sticking to principles declarations and (actively?) supporting aligned, autonomous grassroots movements to take off on their own. All religious creeds are entitled to the same prerogatives, though only if satisfying somewhat strict requirements: for instance, for celebrating marriage on behalf of the State. All confessions are to be self-financing.