Mack (1974), together with by Kurt Forster (1976) and Howard Saalman (1966) have interpreted the evidence differently, arguing that that work on the facade would have awaited the acquisition of the third property along the Via della Vigna Nuova and was stimulated by the engagement of Rucellai's son Bernardo to Piero di Cosimo de' Medici's daughter Nannina in 1461. According to this theory it could only have been after the betrothal, that the pairing of clearly identifiable Medici devices with those of the Rucellai in the friezes could have been permissible. The same is case for the Medici interlocking rings insignia that occupy the spandrels of the windows. That would postpone construction of the Rucellai facade to a date after 1461 and calls into question its primacy over the almost identical design used for the Palazzo Piccolomini (designed by Bernardo Rossellino 1459-62) in the papal city of Pienza.