Passive + por + Agent

Passive Agent with Por

Level 4

In the passive voice (e.g., 'The book was written by me'), the 'agent' is the doer. In Portuguese, this is almost always introduced by the preposition por (by), which contracts with articles to become pelo, pela, pelos, or pelas.

How It Works

The agent of the passive is the element that performs the action when a sentence is inverted from active to passive voice.

1. The Transitivity Rule
Typically, transitive direct verbs (verbs that take a direct object without a preposition) are converted into the passive voice. While most verbs requiring a preposition (like gostar de) cannot be passivized, there are notable exceptions in Portuguese: verbs like obedecer, desobedecer, and perdoar are frequently used in the passive voice (e.g., 'Ele foi obedecido pelos soldados').

2. Formation and Contractions
The preposition por must contract with definite articles. This is a mandatory rule in Portuguese:

  • por + o = pelo
  • por + a = pela
  • por + os = pelos
  • por + as = pelas

Note that por does not contract with indefinite articles (um, uma, uns, umas). You write 'por um' or 'por uma' separately.

3. Agreement Rules
In the passive voice, the past participle must agree in gender and number with the subject (the receiver), NOT the agent (the doer).
Example: A carta (fem. sing.) foi escrita (fem. sing.) pelo João.

4. The use of 'De'
In modern Portuguese, por is used for almost everything. However, with verbs involving emotion, reputation, or mental states (like amar, estimar, conhecer, respeitar), you may see de used as the agent marker in formal or literary writing (e.g., 'Ele é amado de todos').

5. Register and Usage
While the passive voice with an explicit agent is common in journalism and formal writing, spoken Portuguese often avoids it to sound less heavy. In casual conversation, speakers prefer the active voice or the passive 'se' construction. When using the 'se' construction, however, you cannot include an agent with 'por'; if the doer is important to mention, the active voice is almost always used instead.

Examples (5)

  1. O bolo foi feito pela minha avó.

    The cake was made by my grandmother.

    Word by Word: The cake was made by-the my grandmother.

    Here, 'pela' is the contraction of 'por + a'. The participle 'feito' agrees with the masculine subject 'o bolo'.

  2. As cidades foram destruídas pelo temporal.

    The cities were destroyed by the storm.

    Word by Word: The cities were destroyed by-the storm.

    The agent 'pelo temporal' explains what caused the destruction. Note that 'destruídas' is feminine plural to match 'as cidades'.

  3. Este livro foi escrito por mim.

    This book was written by me.

    Word by Word: This book was written by me.

    When the agent is a pronoun like 'mim', no contraction occurs with 'por'.

  4. A decisão será tomada pelo diretor.

    The decision will be taken by the director.

    Word by Word: The decision will-be taken by-the director.

    This shows the passive agent used in the future tense.

  5. Ele é respeitado de todos os colegas.

    He is respected by all his colleagues.

    Word by Word: He is respected of all the colleagues.

    An example of the literary use of 'de' as an agent marker with a verb of emotion/state.

Common Mistakes

  • Using 'por o' or 'por a' instead of the mandatory contractions.

    O livro foi lido por o aluno.
    O livro foi lido pelo aluno.

    In Portuguese, 'por' must always contract with the definite article that follows it.

  • Matching the participle's gender/number with the agent instead of the subject.

    A casa foi construído pelo pedreiro.
    A casa foi construída pelo pedreiro.

    The participle 'construída' must agree with the subject 'a casa' (feminine), even though the agent 'o pedreiro' is masculine.

  • Adding an agent with 'por' to a 'se' passive construction.

    Alugam-se casas pelo corretor.
    Casas são alugadas pelo corretor.

    The synthetic passive (with 'se') does not allow an explicit agent. If you want to name the agent, you must use the analytical passive with 'ser'.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

Passive + por + AgentLevel 4Passive Agent with Por

Learn This First

To introduce the agent of a passive action (the 'doer'), you first need to learn the basic passive voice structure (Ser + Participle). You also need to be familiar with the preposition 'por' and its mandatory contractions (pelo, pela, etc.), as these are used to link the action to the person or thing performing it.

Words in This Pattern