The First Battle of Öland (), was part of the Nordic Seven Years War (1563-1570), which broke out as a result of King Erik XIV’s claim for dominion over the Baltic Sea, which "challenged the trade interests of both Denmark and the Hanseatic city of Lubeck". It took place on 30–31 May 1564 between the islands of Gotland and Öland, off the northern tip of Öland, between a Dano-Lübeckian fleet of 36 ships, the Danes under Herluf Trolle and the Lübeckers under Friedrich Knebel, and a Swedish fleet of 38 ships under Admiral Jakob Bagge.
Ships involved
Denmark/Lübeck
- Fortuna (Danish flag)
- Byens Løffue 56
- Engel (Lübeck flag)
- Lange Bark (Lübeck) — sunk 30 May
- Arck
- Fuchs (Lübeck)
- other ships
Sweden
- Mars 173 (flag) — blew up 31 May
- The flagship of the Swedish fleet, Swedish battleship Mars (also known as the Makalos [Matchless] or the Jutehatar), the largest in the Baltic at the time at more than 45m long and carrying 173 guns (some sources debate between 100-200), was constructed from 1561-1564, under instruction from master shipwright Holgerd Olsson (Master Hollinger).