Most world titles, different weight divisions, simultaneously

Most world titles, different weight divisions, simultaneously
Who
Unknown
When
01 January 0001
Most different weights
The feat of holding world titles at three weights simultaneously was achieved by Henry `Homicide Hank' Armstrong (USA) (1912-88), at featherweight, lightweight and welterweight from August to December 1938. It is argued, however, that Barney Ross (b. Barnet David Rosofsky, USA) (1909-67) held the lightweight, junior-welterweight and welterweight, simultaneously, from 28 May to 17 September 1934 (although there is some dispute as to when he relinquished his lightweight title).
In recent years there has been a proliferation of weight categories and governing bodies but Armstrong was undisputed world champion at widely differing weights which makes his achievement all the more remarkable.