Two of Wall Street’s oldest law firms are celebrating major milestones this year: Cravath, Swaine & Moore turns 200 years old, while Sullivan & Cromwell—founded when Thomas Edison was still tinkering with his first electric light bulbs—turns 140. Another elite New York firm, Wachtell, Lipton, Rosen & Katz, is relatively young—about 54 years old—but in its relatively short life has grown to be one of the premier M&A firms competing for Wall Street business.

SEE ALSO: Can Cravath and Wachtell’s Lean Lockstep Approach Keep Them on Top? and High-End M&A Meets a New Challenge: Too Many White Men

While each of the firms’ practice mix has evolved over generations, other attributes have held constant, including their financial prosperity and high profits, and their partners expect to maintain longtime traditions unique to each firm.