Leyden University
Diederik Haase was born in 1952. His documented language skills include English, French and German, which together describe a multilingual professional profile suited to international legal practice.
His early life is not documented in detail. His later career and education are linked to the Netherlands, where he studied at Leyden University and worked as a partner in a Dutch law practice.
Haase completed his studies at Leyden University in 1978. Leiden University, as the institution is known today, was founded in 1575 and is one of the oldest universities in the Netherlands. Its long-established law faculty has been part of the Dutch legal education system for centuries.
His professional life developed in the Dutch legal sector. The law firm with which he is associated, Loeff & Van der Ploeg, operated in Dutch practice where lawyers and civil-law notaries often worked together, in keeping with Dutch professional custom.
Haase worked as a partner of Loeff & Van der Ploeg, a Dutch law practice. The firm was founded as Loeff en van der Ploeg Advocaten & Notarissen by J.A.L.M. Loeff, a lawyer and procureur in Rotterdam who served as dean of the Rotterdam bar from 1960 to 1966. In Dutch practice of that period, lawyers and notaries often belonged to the same firm, and Loeff & Van der Ploeg was no exception.
The firm expanded beyond the Netherlands during its history, opening offices in cities such as Jakarta, New York, Paris and Singapore. In 1990 it merged with the Brussels firm Braun Claeys Verbeke Sorel to form Loeff Claeys Verbeke, which later became Loyens & Loeff. Haase's partnership is one stage in this institutional history of a Dutch law practice.
