Sir William Schwenck Gilbert (1836- 1911)

Sounds pretty German to me. No clue though- wiki has no answer.

But this is pretty interesting:

On 29 May 1911, Gilbert was giving swimming lessons to two young ladies in the lake of his home Grim's Dyke when one of them lost her footing and called for help. Gilbert dived in to save her, but suffered a heart attack in the middle of the lake and drowned.