Latin has a perfect tense ().

.librumēmi
Latinbook:ACC.SGbuy.PRF:1.SG
I have bought a book

This survived in the Romance languages as a perfective past tense (exemplified by the last word in below). The perfect, however, was renewed in Vulgar Latin. The Latin word for ‘have’ is habere ().

.librumhabeo
Latinbook:ACC.SGhave(PRS):1.SG
I have a book

Classical Latin may expand this construction by a passive participle in the function of a predicative complement to the direct object. illustrates this construction in a Vulgar Latin adaptation.

.habeolibrumcomparatum
Latinhave(PRS):1.SGbook:ACC.SGbuy:PTCP.PRF:ACC.SG
I have bought a book

In Classical Latin, this construction implies that the actor has the undergoer at topic time. It may still have this sense in ancient Portuguese ().

.Duascousasheieupostasemnomeucoraçom.
Porttwo:F.PLthing(F):PLhave.PRS.1.SGIput:PTCP.PRF:F.PLin:DEF.M.SGmy:M.SGheart(M)
Two things have I put in my heart.(Livro dos Mártires, p. 128a, 14th cent.)

In this phase of the grammaticalization process, the participle still agrees with the direct object in gender and number. Almost at the same time, however, the possessive sense vanishes in the evolving periphrastic construction. Here the verb haver functions as an auxiliary and the participle as the non-finite form of the full verb. Due to the syntactic relations in the source construction, this periphrastic perfect is initially limited to transitive verbs. In Old Portuguese, it becomes possible with intransitive verbs, too ().

.heiemmagrecidoeenvelhecido
Porthave.1.SGgrow.thin:PRTCP.PRF:Mandgrow.old:PTCP.PRF:M
I have grown thin and old(Tycho Brahe Platform, Carta 450)

Up to this point, the development resembles the story of the Old English perfect (ch. 3.2.3). So the Latin verb habere is now grammaticalized, not only as a perfect auxiliary, but also in other grammatical functions. In Old Portuguese, haver may still have its lexical sense ().

....queeuauiaquejaonãohei
PortthatIhave:IMPF:1.SGthatalreadyitnothave:1.SG
[the problem] which I had, that I don't have it any more,
 quejaoperdi.
thatalreadyitlose:PRT.1.SG
that I already lost it.
(Vida e Milagres de Santa Senhorinha de Basto, p. 304v, 13th cent.)

In Modern Portuguese haver is no longer used as a verb of possession. It is renewed, in this function, by desemanticizing Latin tenere ‘hold’. contrasts the original use of the latter with habeo ().

.librumteneo
Latinbook:ACC.SGhold(PRS):1.SG
I hold a book

This verb is ter in Modern Portuguese and just means ‘have’; translates .

.tenhoumlivro
Porthave(PRS):1.SGINDF:M.SGbook(M)
I have a book

The verb ter has been used in this sense since the ancient Portuguese period ().

.nemtenhoferramẽtatalcomqueacaue
Portnorhave(PRS):1.SGtoolsuchwithREL3.SG.Fdig:PRS.SUBJ.1.SG
nor do I have a tool with which I might dig it [the earth](Vida de Santa Maria Egipcíaca, p. 133; 1275-1325)

Although the periphrastic perfect illustrated by is not yet very old, the verb haver is replaced by ter not only in its possessive sense, but also in its function as perfect auxiliary. If one is to trust the documentary evidence, this happened just a little later than the onomasiological change in the lexeme ‘have’. Thus, the construction of replaces the construction of f.

.tenhoperdidaameatadedamjnhaalma
Porthave(PRS):1.SGlose:PTCP.PRF:F.SGDEF.F.SGhalf(F)of:DEF.F.SGmy:F.SGsoul(F)
I have lost half of my soul(Vida do honrado Infante Josafat, filho d’el Rei Avenir, p. 17v, 1375-1400)

The gender and number agreement of the participle with the direct object is a trait of persistence of the source construction, in which the two are in a predicative relation. This agreement is lost with further grammaticalization. In modern Portuguese, the sentence would read tenho perdido a metade da minha alma, with the default form of the non-finite verb form.

The Portuguese dialects differ slightly in the aspectual function of this construction: In European Portuguese, it is a perfect progressive; in Brazilian Portuguese, it is just a perfect, as it is already in .

This is a story of multiple replacements. The constant factor is the functional category of the perfect. The contemporary perfect has the same function as the perfect had one and a half millennia ago. It was renewed twice: first the synthetic Latin perfect was renewed as a periphrastic perfect, then this periphrastic perfect was renewed by replacing its auxiliary. The latter renewal is apparently a side effect of the onomasiological change in the lexeme ‘have’, which was itself renewed.