Hi Katherine,

Thank you for contacting Mearto with your appraisal inquiry.

The Letters of St. Catherine of Siena are a cornerstone of Christian spirituality, medieval literature, and church history. Catherine (1347–1380), a Dominican tertiary, was known for her deep mystical experiences and intense devotion to Christ. Her letters reflect personal spirituality, mystical theology, and guidance for moral life. Many letters were written to rulers, clergy, and ordinary people, urging reform, penitence, humility, and adherence to God’s will. They illustrate a blend of contemplative spirituality and active engagement in worldly affairs. The letters articulate ideas about God’s love, human responsibility, and the Church’s spiritual mission, later contributing to her canonization (1461) and Doctor of the Church designation (1970).

Catherine wrote to popes, cardinals, and secular rulers, most famously Pope Gregory XI, urging the return of the Papacy from Avignon to Rome. These letters are key primary sources for 14th‑century church politics and the Avignon Papacy crisis, advocating for peace, reform, and ethical leadership, that show the influence a single religious figure could wield in medieval Europe.

Catherine’s letters are still read for spiritual formation, ethical guidance, and pastoral inspiration, providing practical advice for leaders, clergy, and laypeople.

Because I can't be 100% certain who or when this was published - an antiquarian bookseller who is able to examine this in person might be able to identify that - but what I can tell is that it was printed on laid paper (as opposed to wove paper) and has a slight texture as it was formed on a mold with laid lines - you can see these in the photo but they're most notable when held up to the light. This type of paper making was introduced in the Medieval (13th Century) and continued to the mid 18th Century (around 1750), when technology changed and 'wove paper' (which has a more uniform smooth and even surface) became more predominant among artists and book publishers.

This was almost certainly printed in Italy and probably in the 15th or 16th Century; the drawing of the solder was a later (19th Century) addition; the script writing was also inserted at some time after it was printed.

Without know the publisher or date, I'm being a bit cautious with my valuation but based on what other 16th and 17th Century Italian texts are currently selling for at auction, I would expect it to sell for between $3,000 and $5,000 if offered by an auction house that has a dedicated books and manuscripts department.

Based on the photos and information provided, and subject to examination, this is:

Italian School, 16th-17th Centuries
Letters of St Catherine of Siena
nearly 1050 pages, bound in white vellum, inscribed to the spine, with later inscriptions
9 by 6-1/2 inches
CONDITION: With wear commensurate to age and use.
PROVENANCE: Unknown
$3,000-5,000*
*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, or questions/concerns, and thank you again for using Mearto.
~ Delia