Dictionary of Medieval Names
from European Sources

Thaddeus m. Aramaic תדי '(courageous) heart'.

The name of one of the twelve Apostles. Wycliffite Bible (1395): Tadee.

Italy
Latin
1243 Tadeum (acc) hennes-vol1 110; 1285 Tadei (gen) Perugia1285 p. 156; 1514 Thadeus (nom) Rossi-StudiStoria p. 274
Italian
1513x1521 Thadeo LeoX p. 14
Cite as: S.L. Uckelman. "Thaddeus". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2016, no. 4. http://dmnes.org/2016/4/name/Thaddeus.