Ah, Constantine! what mischief in the gift —
Not thy conversion, but the dower you gave
For the first wealthy Father to receive.

[Ahi, Costantin, di quanto mal fu matre,
non la tua conversion, ma quella dote
che da te prese il primo ricco patre!]

Dante Alighieri (1265-1321) Italian poet

The Divine Comedy [Divina Commedia], Book 1 “Inferno,” Canto 19, l. 115ff (9.115-117) [Dante] (1309) [tr. Bannerman (1850)]
    (Source)

According to legend, the Emperor Constantine, having been cured of leprosy through baptism by Pope Sylvester, both showered Sylvester with riches and moved his own capital to Constantinople, leaving the Pope as temporal ruler of the West. This "Donation of Constantine" was fabricated in the 8th century, and first used by Pope Adrian I to encourage Charlemagne to give generously and acknowledge papal power over the emperor. It was largely believed true until the 15th Century. Dante, both author and character, traced the Church's corruption by power and wealth from that legend.

(Source (Italian)). Alternate translations:

Ah! Constantine, of how much ill was Cause
Not thy Conversion, but those rich Domains
That the first wealthy Pope received of thee!
[tr. Milton (1641)]

Ah, Constantine, what are the many Ills
You have been parent of: I do not mean
By your Conversion, but that pompous Gift
By which our Holy Father you enrich'd!
[tr. Rogers (1782), l. 112ff]

Lamented ever be that lib'ral hand,
Whose gifts allur'd the Apostolic band
To leave that humble path where long they trod.
[tr. Boyd (1802), st. 19]

Ah, Constantine! to how much ill gave birth,
Not thy conversion, but that plenteous dower,
Which the first wealthy Father gain’d from thee!
[tr. Cary (1814)]

Ah, Constantine! what ills have we to rue --
I say not from thine own conversion sprung,
But from thy dower, the first rich father drew!
[tr. Dayman (1843)]

Ah Constantine! to how much ill gave birth, not thy conversion, but that dower which the first rich Father took from thee!
[tr. Carlyle (1849)]

Oh, Constantine, of how much ill the source!
Not thy conversion, but that fatal dower
Which the first Father took from the in gift!
[tr. Johnston (1867)]

Ah, Constantine! of how much ill was mother,
⁠Not thy conversion, but that marriage-dower
⁠Which the first wealthy Father took from thee!
[tr. Longfellow (1867)]

Ah, Constantine, of how great ill was mother, not thy conversion, but that dowry which the first rich pope got from thee!
[tr. Butler (1885)]

Ah, Constantine, of how much ill was cause,
Not thy conversion but the fatal dower
Which the first wealthy father from thee draws!
[tr. Minchin (1885)]

Ah Constantine! of how much ill was mother, not thy conversion, but that dowry which the first rich Father received from thee!
[tr. Norton (1892)]

Ah! Constantine, of how great ill was mother,
Not thy conversion, but that fatal dowry,
Which from thy hands received the first rich Father.
[tr. Griffith (1908)]

Ah, Constantine, of how much evil gave birth,
not thy conversion, but that dower
the first rich Father had from thee.
[tr. Sinclair (1939)]

Ah, Constantine, what evil fruit did bear
Not they conversion, but that dowry broad
Thou on the first rich Father didst confer!
[tr. Binyon (1943)]

Ah, Constantine! What ills were gendered there --
No, not from thy conversion, but the dower
The first rich Pope received from thee as heir?
[tr. Sayers (1949)]

Ah Constantine, what evil marked the hour --
not of your conversion, but of the fee
the first rich Father took from you in dower!
[tr. Ciardi (1954)]

Ah, Constantine, of how much ill was mother, not your conversion, but that dowry which the first rich Father took from you!
[tr. Singleton (1970)]

Oh, Constantine, what evil did you sire,
not by your conversion, but by the dower
that the first wealthy Father got from you!
[tr. Musa (1971)]

Ah, Constantine, what wickedness was born --
and not from your conversion -- from the dower
that you bestowed upon the first rich father!
[tr. Mandelbaum (1980)]

Ah, Constantine, how much ill you produced,
Not by your conversion, but by that endowment
Which the first rich father accepted from you.
[tr. Sisson (1981)]

Ah Constantine! What measure of wickedness
Stems from that mother -- not your conversion, I mean:
Rather the dowry that the first rich Father
Accepted from you!
[tr. Pinsky (1994), l. 108ff]

Ah, Constantine, not your conversion, but that dowry which the first rich father took from you, has been the mother of so much evil!
[tr. Durling (1996)]

Ah, Constantine, how much evil you gave birth to, not in your conversion, but in that Donation that the first wealthy Pope, Sylvester, received from you!
[tr. Kline (2002)]

What harm you mothered, Emperor Constantine!
Not your conversion but the dowry he --
that first rich Papa -- thus obtained from you!
[tr. Kirkpatrick (2006)]

Ah, Constantine, to what evil you gave birth,
not by your conversion, but by the dowry
that the first rich Father had from you!
[tr. Hollander/Hollander (2007)]

Ah, Constantine, the evil thrown in the world
Was not your conversion to Christ, but the wealth and grandeur
The first rich Pope and Father took from your hands!
[tr. Raffel (2010)]

Constantine! You set the spurs
To evil, not by cleaving to your new
Religion, but by how, when you moved east,
You gave Sylvester, just to stay behind,
The Western Empire's wealth.
[tr. James (2013)]