Dictionary of Medieval Names
from European Sources

Isaac m. Hebrew יִצְחָק '[he] will laugh'.

The name of a Biblical patriarch. Wycliffite Bible (1395): Isaac.

England
Latin
1222 Ysaac (nom) StPaulDom p. 101; 1279–80 Isak (nom) WaHR-SK p. 36
Dutch
1572 Isaac AuFr Bontenaken, Isaack ibid. Bogarts; 1574 Isaack ibid. Costere, Isack ibid. Dierecksen; 1576 Isaac ibid. Assendelft, Isaack ibid. Clerx; 1579 Isaac ibid. Engelgrave; 1581 Isaac ibid. Gast; 1583 Isaac ibid. Engelgrave; 1584 Isaac ibid. Brauwers; 1587 Isaac ibid. Brugge, Isaak ibid. Bogaerts; 1590 Isaack ibid. Cleijmans; 1591 Isaac ibid. Beun; 1592 Isaac ibid. Buen; 1593 Isaac ibid. Alaerts; 1594 Isaack ibid. Baert; 1596 Isaac ibid. Connick; 1597 Isaac ibid. Freschner; 1599 Isaac ibid. Clerck
Finland
Early Modern Swedish
1582 Isack (nom) Audén1980 p. 171
France
Latin
1378 Ysaco (dat) hanquetvol1 1169
Middle French
1562 Isaac RegPCC-1 p. 14; 1563 Isaac ibid. p. 24; 1564 Isaac ibid. p. 55, Ysaac ibid. p. 90; 1565 Isaac ibid. p. 189, Ysaac ibid. p. 163; 1566 Isaac ibid. p. 215, Ysaac ibid. p. 218; 1567 Isaac ibid. p. 292, Ysaac ibid. p. 328; 1568 Isaac ibid. p. 373, Ysaac ibid. p. 374; 1570 Isaac ibid. p. 426
Ireland
Latin
fin12thC Isaac (nom) MunDocIr III, p. 17
Italy
Latin
1237 Ysaki (gen) TirNot1 584; 1527 Jsach (nom) Rome1527 p. 87
1285 Ysacutii (gen) Perugia1285 p. 154
Scotland
Latin
1238 Ysaaco (abl) CartLevenax p. 13
Switzerland
Latin
1188 Ysaac (nom) CartHaut 28
Cite as: R. Le Get, S.L. Uckelman. "Isaac". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2016, no. 4. http://dmnes.org/2016/4/name/Isaac.