Lucrezia, he painted many Lucrezia portraits!
Portrait of Johannes Cuspinian 1502. Cesare Borgia had a hat just like this one.

Raphael after the Mona Lisa.
Lady with a Unicorn close-up. Lucrezia Borgia.
Lady with a Unicorn as St. Catherine - restored 1935 after an X-ray.
Christ And Mary Painting by Lucas Cranach the Elder. Da Vinci Code fans might say this is Jesus and Magdalene. Cranach did Lucrezia as Lucrezia the Etruscan paintings, is this she as well?
Titian.
 Bernardino Luini - Saint Catherine after Leonardo.
St. Catherine.
St. Catherine.
Magdalene, and her alabaster jar.
Raphael.
Raffaello Sanzio - Isabel.
 "El Suplicio de Cuauhtémoc" by Leandro Izaguirre (1867-1941) done in 1893 on display at the Museo Nacional de Arte in Mexico City. Something else that was going on at the time...in the Americas.
The Borgia apartments in the Vatican, The Dispute of St. Catherine - Lucrezia as St. Catherine.
St. Catherine.
Hercules II. D'Este, Duke of Modena and Ferrara (1508-1559 ... Lucrezia Borgia Cameo. Lucrezia when she married the Duke of Ferrara.
The Duke of Ferrara.
He was a Cardinal until his old age.
Lucrezia in charge of the Vatican in the absence of the pope.
Lucrezia and Rodrigo Pope Alexander VI.
La sala del Palacio Borja Ducal a Gandia, Spain.
By Raphael in the Vatican.
Lucrezia was an herbalist, see her portrait as Flora below - the sprig she is holding could have medicinal properties.
Allegory of Boat, Wolf, and Eagle - by Leonardo da Vinci. It is said that the wolf is the current pope who is steering the boat of the church towards earthly glory (the eagle on the globe).
Caterina Sforza - the Tigress of Forli.
Idealized Portrait Of A Courtesan As Flora Painting by Bartolomeo Veneto - Lucrezia Borgia.
By Paris Bordone - message on a wax tablet.
Titian - Portrait of a Man with a Quilted Sleeve.
Titian from "Sacred and Profane Love".
Mona Lisa pose - Renaissance - Isabel.
Lucretia – Quadreria Palazzo Magnani Quadreria Palazzo Magnanio The Collection.
This is "Lucrezia" but it is Etruscan Lucrezia which is pre-Roman.

Lucrezia as Lucrezia?
 Parmigiano - "Lucrezia". 
Cesare Borgia as Jesus.
"The Dispute of St. Catherine" - here we have Lucrezia Borgia as St. Catherine again.
Lucrezia Borgia.