Art historians continually use concepts of art, i.e., they continually distinguish between art and non-art. Before initiating their art historical inquiries, they have to decide which items are eligible for inclusion in the historical study of art and which are not. Their categorization choices are weighty because artefacts that are considered to be art are elevated over other cultural practices. Nonetheless, current concepts of art are deficient, as they showcase biased features: aesthetic artefacts made by minority groups, most notably culturally remote groups, lower socioeconomic classes and women, are largely excluded from or have a marginalized place in art historical inquiries. Art historians provide deficient justification for their categorization choices. The challenge is to provide optimized concepts of art for art historians in order to avoid unwarranted exclusions. To achieve this goal, I will develop a normative account of art: rather than merely clarifying or systematizing the criteria underlying current concepts of art (cf. the method of conceptual analysis), which is what most philosophers of art are after, I aim to offer revised criteria for distinguishing between art and non-art that are more suitable for realizing the tasks or purposes these concepts are put to (cf. the method of conceptual engineering). The work that needs to be done can be divided in three phases: (I) an examination of art historians’ usage of the concept of art; (II) a formulation of the background standards against which evaluation of art historians’ concepts of art will proceed, namely, the possible purposes art historians might legitimately aim to fulfil; and (III) a development of the criteria that will be used to optimize art historians’ use of the concept of art. In this way, the project both contributes to the philosophical project of defining art and provides improved conceptual tools for art historians.