text: In December 1435, at age 56, tired of the unstable character of his single life, Poggio left his long-term mistress and delegitimized the fourteen children he had had with her, scoured Florence for a wife, and married a girl of a noble Florentine family, not yet 18, Selvaggia dei Buondelmonti. In spite of the remonstrances and dire predictions of all his friends about the age discrepancy, the marriage was a happy one, producing five sons and a daughter. Poggio wrote a spate of long letters to justify his move, and composed one of his famous dialogues, An seni sit uxor ducenda (Whether an old man should marry, 1436).
  Poggio also lived in Florence during the Council of Florence, from 1439 to 1442.
  Dispute with Valla
  In his quarrel against Lorenzo Valla—an expert at philological analysis of ancient texts with a hot temperament fitted to protracted disputation—Poggio found his match. Poggio started in February 1452 with a full-dress critique of the Elegantiae, Valla's major work on Latin language and style, where he supported a critical use of Latin eruditio going beyond pure admiration and respectful imitatio of the classics.
  At stake was the new approach of the humanae litterae (profane classical Greek and Latin literature) in relation to the divinae litterae (biblical exegesis of the Judeo-Christian "sacred scriptures"). Valla argued that biblical texts could be subjected to the same philological criticism as the great classics of antiquity. Poggio held that humanism and theology were separate fields of inquiry, and labeled Valla's mordacitas (radical criticism) as dementia.