徐汇 is named after
徐光启 (1562-1633), the late-Ming official and Catholic convert who collaborated with Matteo Ricci to translate Euclid's Elements into Chinese. His family estate at the confluence (
汇) of two creeks became the area's core; the 1847 Jesuit
徐家汇 settlement — with its observatory, library, and St. Ignatius Cathedral — turned the district into Shanghai's intellectual heart.