This battle took place on 30 and 31 May 1564 between the islands of Gotland and Öland, between a fleet of Allied ships, the Danes under Herluf Trolle and the Lübeckers under Knebel, and a Swedish fleet of 23 or more ships under Jakob Bagge. It was an Allied victory. May 30 is the 150th day of the year in the Gregorian calendar (151st in leap years). ... May 31 is the 151st day of the year in the Gregorian calendar (152nd in leap years), with 214 days remaining, as the last day of May. ... Events March 8 - Naples bans kissing in public under the penalty of death June 22 - Fort Caroline, the first French attempt at colonizing the New World September 10 - The Battle of Kawanakajima Ottoman Turks invade Malta Modern pencil becomes common in England Conquistadors crossed the Pacific Spanish found a colony...

Only some of the ships on each side were involved, the rest being unable to help due to the wind. On 30 May Fortuna was damaged and Lange Bark sunk, but on 31 May Mars was boarded by Byens Løffue, Engel and Fuchs before catching alight and exploding, killing most of its crew and 300 boarders. Jakob Bagge and his Second, Arved Trolle, were taken prisoner. Swedish casualties apart from in this ship were 101. Fleming took over the fleet and sailed it back to Elfsnabben, while the Danes sailed to Copenhagen.

Ships involved:

Denmark/Lübeck

Fortuna (flag)
Byens Løffue 56
Engel (Lübeck flag)
Lange Bark (Lübeck) - Sunk 30 May
Arck
Fuchs (Lübeck)
other ships

Sweden (Jakob Bagge)

Mars 173 (flag) - Blew up 31 May
Elefant 65 (Fleming)
Finska Svan 82
Svenska Hektor 87
19 or more other ships