Ranieri Tonissi S.p.A. - founded in 1886 - became Agent of M.A.N. in 1948 for marine and industrial medium speed engines.
SIRN S.r.l. - founded in 1947 - became Agent of Burmesteir & Wain in 1979 for marine and industrial low speed engines.
On 1981 M.A.N. took over the Diesel engines activity of B&W with the foundation of MAN B&W Diesel AG.
From 1981 to 2009 Ranieri Tonissi S.p.A. and SIRN S.r.l. have operated in full cooperation as two Agencies for Medium and Low speed engines.
On May 2009 the two Companies established Sirn & Tonissi United S.r.l. who is nowadays the unique Italian Agent of MAN Diesel & Turbo SE.