The following information is taken from the Dictionary of the Older Scottish Tongue, available online at http://www.dsl.ac.uk/index.html. This is a work in progress.
| Spelling | Number | Dates & headers | 
|---|---|---|
| Issobell | 12 | 1544 (cale); 1551 (cleid); 1595 (curatrix); 1596 (bewich); 1596-7 (casting); 1601 (convoy); 1626 (blude); 1637 (barne-bed); 1640 (bursin, covenanter); 1647 (dauchter) | 
| Isobell | 8 | 1500 (aunt); 1515 (cautionar); 1536 (conjunct); 1572 (cosingnace); 1576 (coupnocht); 1577 (dansar); 1632 (clattie); 1643 (brasin) | 
| Isabell | 4 | 1466 (content); 1473 (brigantine); 1535 (conjunct); 1562 (brute) | 
| Isabel | 2 | 1397 (brother); 1405 (cum) | 
| Isbell | 1 | 1596 (commixtioun) | 
| Isobel | 1 | 1563 (air) | 
| Isoble | 1 | 1648 (brankis) | 
| Izabell | 1 | 1397 (conditioun) | 
| Ysabell | 1 | 1501 (cautioun) | 
| Ysobell | 1 | 1525 (cousinace) |