Another hand that can be isolated is that of the painter known as the Karlsruhe Master, named after the panel of the Adoration of the Child (Karlsruhe, Staatl. Ksthalle), to whom several works, including Christ on the Cross with Four Saints (Madrid, Mus. Thyssen-Bornemisza) and the Scenes from Monastic Life (Florence, Accad.), can be attributed (Pope-Hennessy, 1950).

The Adoration of the Child was taken by Pudelko (1935) as the stylistic basis on which to build the oeuvre of an unidentified artist active in Florence and Prato in the 1440s and 1450s. In Pudelko's opinion, his career probably began in the workshop of Paolo Uccello.

The works attributed to him are strongly influenced by Domenico Veneziano, but later examples make clear reference to Alesso Baldovinetti. The catalogue of frescoes, panels and drawings created by Pudelko for the Karlsruhe Master corresponds very closely to the oeuvre that Salmi (1934) provisionally assigned to the Master of the Quarata Predella, and many of the works attributed to Pudelko's Karlsruhe Master continue to be ascribed to Paolo Uccello or have been claimed for Giovanni di Francesco or the Master of the Castello Nativity. Some have also been described as school of Andrea del Castagno or Florentine school.

The frescoes of the Dispute of St Stephen, the Birth of the Virgin and the Presentation of the Virgin in the chapel of the Assunta, Prato Cathedral, were initially acceptable to Pope-Hennessy as part of the Karlsruhe Master's oeuvre, and he therefore renamed the latter the Prato Master, dating the Karlsruhe Adoration to an earlier phase of the unknown artist's career, long before the Prato frescoes.

Later (1969) Pope-Hennessy amalgamated the work of his Prato Master with parts of the oeuvre of Salmi's Master of the Quarata Predella but rejected the Karlsruhe Adoration and created around this yet another catalogue of works, whose author, identified as active 1440-60, he now called the Karlsruhe Master, as Pudelko had done in 1935.

Owing to the close stylistic links with the work of Paolo Uccello, Parronchi (1974) sought to identify the Karlsruhe Master with Uccello's daughter Antonia (1456-91), whom Vasari and Gaetano Milanesi referred to as a Carmelite nun and painter.

Parronchi's argument rests on the inscription SOROR ANTONIA P. on a panel showing a clerical scene, from S Donato, Polverosa (Florence, Uffizi). Parronchi interpreted the inscription as either 'Sister Antonia, daughter of Paolo' or 'painted by Sister Antonia'.

To this artist he attributed the Karlsruhe Adoration; the Thebaid (Scenes from Monastic Life), also in Pudelko's list; the Virgin and Child, also in Pope-Hennessy's list; and a triptych of the Crucifixion.