NGC 6540 was discovered by William Herschel in 1784 and cataloged as H II.198. While Herschel classified it as a "faint nebula," indicated by his classification in the second group of deepsky objects, this object was longly listed as open cluster, e.g. by Collinder who designated it Cr 364. S. Djorgovski independently "rediscovered" it in September 1986 without noting its identity, when looking for obscured globular clusters in the IRAS Point Source Catalog, labeled it Djorg 3, and suspected it to be a globular cluster (Djorgovski 1987). It was finaly Bica et.al. (1994) who identified it with the NGC object, and confirmed its nature as a globular cluster.