What is "ludlum"

Ludlum is a surname. Notable people with the surname include:

• David M. Ludlum (1910–1997), American historian, meteorologist, Army Officer, entrepreneur and author
• George Ludlum Hartford (1864–1957), American businessperson
• Robert Ludlum (1927–2001), American author
• Robert Ludlum (Catholic martyr) (died 1588), British Roman Catholic martyr