| Honorific Prefix: | The Reverend |
| Casimir Zeglen | |
| Honorific Suffix: | CR |
| Birth Name: | Kazimierz Żegleń |
| Birth Date: | 4 March 1869 |
| Birth Place: | Kaczanówka, Austria-Hungary (now Ukraine) |
| Death Place: | unknown |
| Alma Mater: | Warsaw University of Technology |
| Nationality: | Polish |
| Occupation: | priest |
| Known For: | invention of bulletproof vest |
Casimir Zeglen, CR (Polish: Kazimierz Żegleń; 4 March 1869 – before 1927) was a Polish Catholic priest who invented a silk bulletproof vest in the late 19th century.[1] [2] [3] He was a vowed member of the Resurrectionists.
Born in 1869 in Kaczanówka near Tarnopol, at the age of 18 he entered the Resurrectionist Order in Lwów (today Lviv). In 1890, he moved to the United States.
In 1893, after the assassination of Carter Harrison Sr., the mayor of Chicago, he worked on an improved silk bulletproof vest. In 1897, he worked on it with Jan Szczepanik. It saved the life of Alfonso XIII, the King of Spain—his carriage was covered with Szczepanik's bulletproof armour when a bomb exploded near it.
He was the pastor of St. Stanislaus Kostka Catholic Church in Chicago, then the largest Polish church in the country, with 40,000 in the parish. In his early twenties, he began experimenting with the cloth, using steel shavings, moss, and hair. In his research, he came upon the work of Dr. George E. Goodfellow, who had written about the bullet-resistive properties of silk.[4] In his mid-thirties he discovered a way to weave the silk, to enable it to capture the bullet, while visiting weaving mills in Vienna, Austria and Aachen, Germany. A NaNinches thick, four-ply bulletproof vest produced there was able to protect the wearer from the lower velocity pistol bullets of that era.
He died in 1927.