The 1st U-boat flotilla (German "1.
 Unterseebootsflottille") also known as the Weddigen flotilla, was the first operational U-boat unit in Nazi Germany's "Kriegsmarine" (navy).
 Founded on 27 September 1935 under the command of "Fregattenkapitän" Karl Dönitz, it was named in honor of "Kapitänleutnant" Otto Weddigen.
 Weddigen, a U-boat commander during World War I, died on 18 March 1915 after his submarine "U-29" was rammed by the British battleship HMS "Dreadnought" in the North Sea.
German submarine "U-539" was a Type IXC/40 U-boat of Nazi Germany's "Kriegsmarine" during World War II.
 The submarine was laid down on 8 May 1942 at the Deutsche Werft yard in Hamburg as yard number 360, launched on 4 December 1942, and commissioned on 24 February 1943 under the command of "Oberleutnant zur See" Hans-Jürgen Lauterbach-Emden.
 After training with the 4th U-boat Flotilla in the Baltic Sea, the boat was transferred to the 10th U-boat Flotilla for front-line service on 1 July 1943.
 She carried out three war patrols, sinking one ship and damaged two more.
 Transferred to the 33rd U-boat Flotilla on 1 October 1944, she sailed on no further patrols, and surrendered to Allied forces in May 1945.
 Transferred from Bergen, Norway, to Loch Ryan, Scotland, she foundered on 4 December 1945 while being towed to the scuttling grounds as part of "Operation Deadlight".
Karl Dönitz (sometimes spelt Doenitz) (] ; 16 September 1891 – 24 December 1980) was a German admiral who played a major role in the naval history of World War II.
 Dönitz briefly succeeded Adolf Hitler as the head of state of Germany.
The 10th U-boat Flotilla (German "10.
 Unterseebootsflottille") was a German U-boat flotilla used for front-line combat purposes during World War II.
 Founded on 15 January 1942 at Lorient under the command of "Korvettenkapitän" Günther Kuhnke, eighty U-boats operated with this flotilla before it was dissolved on 21 August 1944, and the remaining U-boats were moved to bases in Norway and Germany.
 Kuhnke himself took command of "U-853" , the last U-boat to leave, on 27 August 1944 to sail to Flensburg where he assumed command of 33rd U-boat Flotilla.
German submarine "U-166" was a Type IXC U-boat of Nazi Germany's "Kriegsmarine" during World War II.
 The submarine was laid down on 6 December 1940 at the Seebeckwerft (part of Deutsche Schiff- und Maschinenbau AG, Deschimag) at Wesermünde (modern Bremerhaven) as yard number 705, launched on 1 November 1941 and commissioned on 23 March 1942 under the command of "Oberleutnant zur See" Hans-Günther Kuhlmann.
 After training with the 4th U-boat Flotilla, "U-166" was transferred to the 10th U-boat Flotilla for front-line service on 1 June 1942.
 The U-boat sailed on only two war patrols and sank four ships totalling  gross register tons (GRT) .
 She was sunk on 30 July 1942 in Gulf of Mexico.
German submarine "U-353" was a Type VIIC U-boat of Nazi Germany's "Kriegsmarine" during World War II.
 The submarine was laid down on 30 March 1940 at the Flensburger Schiffbau-Gesellschaft yard at Flensburg, launched on 11 November 1941, and commissioned on 31 March 1942 under the command of "Oberleutnant zur See" Wolfgang Römer.
 After training with the 5th U-boat Flotilla based at Kiel, "U-353" was transferred to the 1st U-boat Flotilla at Brest in France for front-line service from 1 October 1942.
German submarine "U-843" was a Type IXC/40 U-boat of Nazi Germany's "Kriegsmarine" during World War II.
 The submarine was laid down on 21 April 1942 at the DeSchiMAG AG Weser yard in Bremen, launched on 15 December 1942, and commissioned on 24 March 1943 under the command of "Kapitänleutnant" Oskar Herwartz.
 After training with "4th U-boat Flotilla" in the Baltic Sea, "U-843" was transferred to "2nd U-boat Flotilla" on 1 November 1943 for front-line service, and was transferred to "33rd U-boat Flotilla" on 1 October 1944.
 She carried out three war patrols, sinking one ship, and was sunk by a British aircraft in April 1945.
The 8th U-boat Flotilla (German "8.
 Unterseebootsflottille") was formed in June 1941 in Königsberg under the command of "Kapitänleutnant" Georg-Wilhelm Schulz, who also at this time commanded the 6th U-boat Flotilla in Danzig.
 It was primarily a training flotilla but in the last months of the war some flotilla boats were in combat against the Soviet Navy in the Baltic Sea.
 The flotilla was disbanded in January 1945.
German submarine "U-271" was a Type VIIC U-boat of Nazi Germany's "Kriegsmarine" during World War II.
 The submarine was laid down on 21 October 1941 at the Bremer Vulkan yard at Bremen-Vegesack as yard number 36, launched on 29 July 1942 and commissioned on 22 September under the command of "Kapitänleutnant" Curt Barleben.
 After training with the 8th U-boat Flotilla, "U-271" was transferred to the 1st U-boat Flotilla, for front-line service from 1 June 1943.
German submarine "U-1235" was a Type IXC/40 U-boat of Nazi Germany's "Kriegsmarine" during World War II.
 The submarine was laid down on 25 May 1943 at the Deutsche Werft yard at Hamburg, launched on 25 January 1944, and commissioned on 17 May 1944.
 She served with "31st U-boat Flotilla" (31st U-Boat Flotilla), a training unit, and with "33rd U-boat Flotilla" from 1 December 1944 to 15 April 1945.

Question: In what year was the man under whose command the 1st U-boat Flotilla was founded born?
Answer: 1891