These are the earliest known Kastlers who have been mentioned in a document or church records. Persons who are known to have existed earlier than when the church books were starting to be used, typically the mid 1500’s, are considered by me to be rare.
- Christian Kastler – Swabian Kastlers, Farmer, ~*1410 – †1475, Asselfingen, Ulm, Germany
- Simon Kastler – Father at wedding, 1641, Grünbach, Austria
- Petrus Kastler – Catholic Priest, ~*1420 – †1493, Langenau, Ulm, Germany
- Jakob Kastler – Citizen, mentioned 1441, Schaffhausen, Switzerland
- Anthoni Casteler – Wahlern Kastlers, *1565, Wahlern, Switzerland
- Conrad Kastler – Westhoffen Kastlers, †1594, Westhoffen, Alsace, France