Modern sources are divided as to the actual extent of the massacre though they all agree that mass killings did take place. Historian Matthew Kuefler states: "German and Polish historians in the twentieth century tended to have diverging both on the question of whether Pomerelia really "belonged" to Poland and also on the degree of ferocity of the order's conquest". In many Polish works, the takeover is indeed referred to as "Gdańsk slaughter" ("rzeź Gdańska"). similar descriptions are presented also in some other English books with sections on Polish history. Jerzy Lukowski in "A concise history of Poland" says that the knights massacred "Lokietek's men". Błażej Śliwiński says that there was a bloodbath which cost an abundance of lives, though not 10,000, and that such massacres were common in medieval Europe., and that the term "slaughter" in Medieval Ages usually meant murder of around 1000 people.