The names are as follows:

William I (ca. 1167-1222) Count of Holland from 1203
Floris IV (1210-1234 Count of Holland from 1222
Floris V (1254-1296) Count of Holland from 1256
John I (1284-1299) Count of Holland from 1296

The red paint is graffiti. Apparantly the old counts aren't held in respect these days. The council of Rijnsburg doesn't care either.

In 1975 Queen Juliana reburied her predecessors after they were discovered in 1949. In recent times some controversy has arrisen whether the bones are those of the counts. More information: More information:
www.mokumtv.nl/holland2.html
(in Dutch)
and here: www.st-jacob.nl/botoorl.htm