From 1623 he began to make a careful selection of savants who met at his convent in Paris or corresponded with him from all across Europe and even from as far afield as Constantinople and Transylvania (present-day Hungary).
Mula 1623 siya ay nagsimulang gumawa ng maingat na pagpili ng savants na nakikita sa kanyang kumbento sa Paris o corresponded sa kanya mula sa lahat sa buong Europa at kahit mula sa malayo bilang afield bilang Constantinople at Transylvania (kasalukuyan-araw Hungary).