Jochum Tønnesen Müller (Müller is German for Miller). is the earliest recorded person of this family, and is regarded to be the founder of the Jochumsen lineage. He was a captain from the Hanseatic League, who later on settled down in the city of Svaneke. Except from the above, his matters are unknown. He died in 1590.

His tombstone was for a long time used as a part of the floor in the porch of Svaneke Church, with the inscription upwards. It became very worn, and was hard to read. Later on the stone was placed at the churchyard wall, and after some time sold.

It carried the following inscription:

Because of the worn, the name Tønnesen can also be read as Tobiassen.

Jochum Tønnesen Müller was a special type of his time. He was a gifted man with sharp, dark eyes and black hair. These characteristics are said to be the marks of the real Jochumsens. On top of that he was very musical, which also is a characteristic of a lot of people of the lineage (me, for instance).

In "Bornholmian collections of Lineages" the parish clerk Rasmus Pedersen Rafn tells the above, and as well that he had a son.

Jochums Tønnesen Müller's great grandson, Tobias Jochumsen, married Maren Jensdatter, who was the great-granddaughter of the first, trustworthy documented Kofoed, Hans Madsen Kofoed.

This makes the Jochumsen-family an equal part of the Kofoed-family.

The Jochum-name is especially widespread in the Eastern parts of Bornholm - Svaneke, Nexø, Bodilsker, Åker. There is another lineage in Bornholm that uses Jochum-name frequently, namely descendants of Jochum Thiesen and Andreas Thiesen, Svaneke. It seems logic that all user of the Jochum-name has the same starting-point. especially since the Jochum-name is the German version of the name Joachim.

Unfortunately it will probably never be possible to determine if all Jochums in Bornholm are descendants of Jochum Tønnesen Müller.