How do you know when to use subclass of (P279) and influenced by (P737)?Edit
subclass of (P279) must be used if a source qualifies the religion as a part of a larger movement. For example, Catholicism (Q1841) is a denomination of Christianity (Q5043). If no source categorizes the religion as part of a larger movement, then it must be marked subclass of (P279): religion (Q9174). A syncretic religion can be a subclass of many other religions.
influenced by (P737) must be used if a source indicates a line of influence, same if it does not establish a unique claim. For example, Manichaeism (Q131165) is influenced by mazdaism (Q3303092), Buddhism (Q748), and Christianity (Q5043).
Strong influences are likely to be labeled as subclass of (P279). For instance, Vajrayana (Q172175) is usually said to be mainly derived from Mahayana (Q48362) even thought it has been strongly influenced by Shaivism (Q234953), it is thus classified as a type of Buddhism (Q748). However, there may be influenced that do not change the categorization, e. g., Jainism (Q9232) has been influenced by (see derived by) Hinduism (Q9089), but is not a type of Hinduism. You will notice that historical considerations are not the only ones to take into account in the categorization, e. g., Islam (Q432) is generally classified as a Abrahamic religion (Q47280), but not as a type of Catholicism or Judaism.
Why doesn't <such religion> (e.g. «Christianism») derive from <such general concept> (e.g. «monotheism»)?Edit
Because transitivity of inheritance cannot be easily applied, we strongly advocate the use of has quality (P1552) for religious concepts.
First, religion is not just a set of beliefs, it's more than that (think rituals, culture, history, etc.). Some religions don't even have a minimal set of common beliefs (e.g. Buddhisms).
Second, the transitivity of the subclass relationship is a HUGE problem in the case of religions, because a LOT of religions commonly described as inheriting from other ones just wipe out some of their characteristics. For instance, atenism (Q146107) clearly is a subclass of religion of ancient Egypt (Q447131) but should clearly NOT inherit polytheism (Q9163), because it's a Template:(Q! Judaism (a monotheism) can also be a subclass of Canaan religion (from which it derivates), which is an henotheism. Catholicism is also described as a polytheism (with three gods) by islamic sources. See also the example of the Atenism (a monotheism inheriting from a polytheism) or Zurvanism (a polytheism derivating from a monotheism). Etc.
Each characteristic indicated by has quality (P1552) must be added on the element with the highest possible level in the class hierarchy. All derived religions that are subclass of (P279) of this high level religion must have this same characteristic.
If at least one derived religion does not have this characteristic, then the addition of has quality (P1552) must be done at the highest possible level on lower level derived religions in the class hierarchy.
For instance, one might think that Buddhism (Q748) <has quality (P1552)> polytheism (Q9163); however, some religious currents <subclass of (P279)> Buddhism (Q748) are <has quality (P1552)> agnosticism (Q288928) or even atheism (Q7066). Therefore, the property <has quality (P1552)> polytheism (Q9163) should not be attached to Buddhism (Q748) directly, but to the appropriate derived religions.
Is a "church" a religion?Edit
Yes, if the term refers to a doctrine (e.g. Eastern Catholic Church (Q49376)).
No, if the term refers to a formal institution related to a doctrine, if this institution is already filled in as a separate wikidata element.
But one can belong to multiple churches, is that not contradictory?Edit
It is possible to belong to multiple religions (see the Japan case), therefore it is not a criterion for separation.
Que faire des éléments « religion » séparés de « église » ? (fr) – (Please translate this into English.)Edit
FIXME à débattre. (fr) – (Please translate this into English.)
A language code is missingEdit
It often happens that the ancient religious texts are written in an extinct or liturgic language. It is then possible that you could not add it in a qualifier (Wikidata indicating an error saying that the language does not exists). In that case, you must find the code corresponding to the language then follow the process to add a language.