With Portuguese place names, the right question is not simply whether the toponym is feminine. For crase to occur, two things must happen at the same time: the preceding word or expression must require the preposition a, and the place name must take the feminine article a or as. That is why standard Portuguese has vou a Brasília, but vou à Bahia.
The grave accent is only the written sign of this fusion. In à Bahia, the preposition a, required by ir a, combines with the article a used with a Bahia. In a Brasília, the preposition is present, but the name Brasília is normally used without an article. The second a is therefore missing.
The most useful test: vou para, estou em, volto de
To find out whether a toponym takes an article, observe how it behaves with other prepositions. The traditional return test works well: if you say volto da, there is a feminine article, so crase can appear when the governing expression requires a; if you say volto de, the toponym has no article and there is no crase.
| Place | Return form | With a verb requiring a | Result |
|---|---|---|---|
| Brasília | volto de Brasília | vou a Brasília | no grave accent |
| Bahia | volto da Bahia | vou à Bahia | with grave accent |
| Sergipe | volto de Sergipe | vou a Sergipe | no grave accent |
| Paraíba | volto da Paraíba | vou à Paraíba | with grave accent |
| Argentina | volto da Argentina | viajo à Argentina | with grave accent |
| Portugal | volto de Portugal | viajo a Portugal | no grave accent |
| França | volto da França | viajo à França | with grave accent |
| Paris | volto de Paris | viajo a Paris | no grave accent |
| Recife | volto do Recife | vou ao Recife | there is an article, but it is masculine |
The FUNAG Revision Manual records, for example, that a Bahia and a Paraíba are used with the definite article, while Sergipe, Alagoas, São Paulo and other states appear without an article. The same manual also points out the official use of cities that exceptionally take an article, such as o Recife.
The article test does not replace preposition requirements
Finding out that a place takes an article is only half the job. The preceding word must also require the preposition a. Compare:
- Vou à Bahia. The verb ir, in this construction, requires a, and Bahia takes the article a.
- Visitei a Bahia. The verb visitar is direct transitive in this use. The a is only an article, so it does not take a grave accent.
- Fiz uma visita à Bahia. The noun visita can be constructed with a, and the article in a Bahia completes the fusion.
- Refiro-me à Bahia. The expression referir-se a requires the preposition a.
This contrast prevents a common mistake: applying the volto da test and automatically adding a grave accent in every sentence. The test tells you whether there is an article; the governing verb, noun or expression tells you whether there is a preposition.
Why Brasília can appear with a grave accent in some contexts
Toponyms that are normally used without an article may begin to take one when they are specified. Brasília is the classic case. In a neutral form, Portuguese has moro em Brasília, volto de Brasília and vou a Brasília. But a construction such as à Brasília de Juscelino Kubitschek presents the name as determined by a complement, which allows the article and, if the governing expression requires a, produces crase.
The same mechanism explains traditional examples such as à Roma dos imperadores. It does not mean that Roma takes an article in every context. The modifier changes how the name is determined in that sentence.
Fixed expressions: not every grave accent near a place belongs to the toponym
In sentences with fixed expressions, it is important to locate exactly where the fusion occurs. In o hotel fica à direita de Brasília, the grave accent belongs to the expression à direita de. The name Brasília still follows the preposition de, without an article: de Brasília.
In seguimos em direção à Bahia, by contrast, the expression em direção a supplies the preposition a, and Bahia supplies the article a. If the destination is Brasília, the form changes to seguimos em direção a Brasília.
Two different patterns can also appear in the same sentence: o roteiro vai de Brasília à Bahia. The point of departure is de Brasília, while the destination is à Bahia.
Cases that deserve attention
Cities with their own article
Most city names are usually used without an article, but there are exceptions based on official or established usage. O Recife is an important example. Because the article is masculine, Portuguese has vou ao Recife, not à Recife. When a specific toponym is uncertain, check official local usage and standardization references.
Countries and regions
The same reasoning applies to countries, continents and regions. Portuguese has à Argentina, à França and à Europa because these names take a feminine article. Portugal and Angola, in Brazilian usage recorded by official references, appear without an article, producing constructions such as viajar a Portugal and missão a Angola.
Plural forms
If a place name takes the feminine plural article and the governing expression requires a, the fusion can produce às. The principle is the same: preposition a plus article as. What matters is not what the name looks like, but whether that toponym actually takes an article in usage.
Commented exercise
- A equipe viajou __ Brasília.
Answer: a Brasília. The verb allows the preposition a, but the toponym is normally used without an article. - A equipe seguiu __ Bahia.
Answer: à Bahia. There is a preposition a and a feminine article a. - O documentário retrata __ Brasília dos anos 1960.
Possible answer: a Brasília dos anos 1960, if retratar is used directly with its object. There is no preposition required by the verb, even though the toponym is specified. - O texto se refere __ Brasília dos anos 1960.
Answer: à Brasília dos anos 1960. The expression referir-se a requires a preposition, and the specified toponym takes an article. - Vamos visitar __ Bahia no próximo mês.
Answer: a Bahia. Visitar does not require a preposition; the a is only an article. - O grupo seguiu em direção __ Bahia.
Answer: à Bahia. The expression em direção a supplies the preposition and the toponym supplies the article. - O mirante fica __ direita de Brasília.
Answer: à direita de Brasília. The grave accent belongs to the fixed expression à direita de, not to the city name.
A three-question procedure
- Does the preceding word or expression require the preposition a? If not, there is no crase, even if the place takes an article.
- Does the toponym take a feminine article? Test it with estou na or volto da. If the natural form is em or de, there is normally no article.
- Is the name specified, or is it part of a fixed expression? A modifier can make a toponym that normally lacks an article take one, while a fixed expression can contain crase independently of the place name that follows.
To check the spelling and registration of proper names, the Brazilian Academy of Letters' Orthographic Vocabulary is a useful reference. For concrete questions about government and crase, the Academy also maintains ABL Responde, which asks users to submit examples in context.
In short, Brasília and Bahia do not decide the grave accent by themselves. The answer comes from the combination of preposition requirements and article use. Once you separate those two questions, the contrast stops looking like a list of exceptions: vou a Brasília, because there is a preposition without an article; vou à Bahia, because there is both a preposition and an article.
