Liber Orationum Psalmographus (LOP), subtitled The Psalter Collects of the Ancient Hispanic Rite (that is Mozarabic Rite) – recomposition and critical edition, is a unique edition of 591 so-called prayers on psalms or psalm-prayers rendered from Latin orationes super psalmos or orationes psalmicae respectively. They could be defined as short prayers said optionally at the end of a psalm recitation in some Christian liturgies. LOP was published by Jorge Pinell in 1972 (Barcelona-Madrid) as the 9th volume of Monumenta Hispaniae Sacra. The subject, the editor and the date of its publication were closely related to the Second Vatican Council (1962–1965) and the reform of the Latin liturgy begun then within the Roman Catholic Church. The text of LOP can be considered to be the main content of a still missing fifth volume of the Liturgy of the Hours. It was renewed in 1971 according to that Council's principles laid in the Constitution on the Sacred Liturgy Sacrosanctum Concilium. The volume was mentioned in the same year in the General Instruction of the Liturgy of the Hours (para 112), but for some reason has not been published. Psalm-prayers Recitation difficulties The Biblical Psalms are the core of the Divine Office or the Liturgy of the Hours, a Christian prayer practice. Throughout its history, beginning in the pre-Christian era in the context of Jewish religion, believers have been reciting or singing these 150 poems. Scholars point out two main types of this practise in antiquity: so-called cursus cathedralis (a cathedral way of psalms recitation) and cursus monasticus (a monastic way of psalms recitation), which are relevant to the discussion on the modern Divine Office. The cursus cathedralis was characteristic of urban churches where secular clergy, especially bishops, presided over the liturgy, hence an adjective cathedral in the name. It arranged the order of psalms according to the daily solar cycle, which means that specific psalms were sung at sunrise, others at sunset and some during other parts of the day. Their texts corresponded somehow to the day part. The lyrical subjects praise God in a particular time setting, usually mentioned literally. In cursus monasticus, the whole Psalter was recited continuously through the day and night, regardless of content. Such a practise was typical of monasticism. Both ways of reciting the psalms caused some difficulties. The meaning of these Biblical poems was not always clear. Most Christians received the Psalter through the Septuagint,