Namesakes
Danish Prime Ministers:
2 prime ministers
Ludvig Holstein-Holsteinborg 1870-1874 
Ludvig Holstein-Ledreborg 1909
Norwegian Kings and Queens:
1 king
King Karl IV (a.k.a. Ludvig) 1859-1872
Olympic Medalists:
1 bronze, 1 silver
(bronze) Ernst Schultz (a.k.a. Ludvig) 1900 400 m
(silver) Ludvig Dam 1908 swimming - 100 m backstroke
Other Royalty:
2 princes
Wilhelm of Sweden (a.k.a. Ludvig) 1884-1965 Sweden
Erik of Sweden (a.k.a. Ludvig) 1889-1918 Sweden
Swedish Kings and Queens:
1 king
King Karl XV (a.k.a. Ludvig) 1859-1872