Question. Context: Early Netherlandish painting is the work of artists, sometimes known as the Flemish Primitives, active in the Burgundian and Habsburg Netherlands during the 15th-and 16th-century Northern Renaissance; especially in the flourishing cities of Bruges, Ghent, Mechelen, Louvain, Tournai and Brussels, all in contemporary Belgium. Their work follows the International Gothic style and begins approximately with Robert Campin and Jan van Eyck in the early 1420s. It lasts at least until the death of Gerard David in 1523, although many scholars extend it to the start of the Dutch Revolt in 1566 or 1568 (Max J. Friedlander's acclaimed surveys run through Pieter Bruegel the Elder). Early Netherlandish painting coincides with the Early and High Italian Renaissance but is seen as an independent artistic culture, separate from the Renaissance humanism that characterised developments in Italy. Because these painters represent the culmination of the northern European medieval artistic heritage and the incorporation of Renaissance ideals, they are sometimes categorised as belonging to both the Early Renaissance and Late Gothic.

Question: who was one of the first artist to use the netherlandish style of painting?
Answer. Robert Campin and Jan van Eyck
What step-by-step reasoning justifies that answer?
Reasoning: To answer this question, we should know that: Their work follows the International Gothic style and begins approximately with Robert Campin and Jan van Eyck in the early 1420s.