This is Klaus Schilling's translation and summary of http://www.radikalkritik.de/Bolland.htm, which is Hermann Detering's overview of the important Dutch radical critic Gerardus Bolland.
Gerardus Bolland was born in 1854 and had an academic career at Leiden. He became an expert in German idealism, especially von Hartmann and Hegel, and started researching the formation of Christianity in 1891.
Christianity essentially started in the first century among thoroughly syncretic Hellenised Jews in Alexandria. Gnosticising and Hermetic concepts are sensible. The Gospel according to the Egyptians, mentioned in patristic heresiologies, is from those theosophical circles. It could be dated in the decades following the temple fall. Said gospel was a popularising metaphorical representation of gnostic concepts: A salvific mystery around a mythical Chrestos. It was in no way connected to a nationalist Messiah figure.
Chrestos, the son of God, was said to have appeared a few decades before the fall of Zion in human likeness in order to found a new alliance of God and the true (spiritual) Israel just before the old alliance of God and the material people of Israel was going to be flushed down the sewers. The temple of stone had to be superseded by a temple in spirit.
Only after the temple fall, an originally pure mystery deity got transformed into a legendary human. Jesus is named after the successor of Moses, who completed a mission Moses failed to. In allegorical analogy, the gnostic Jesus mystery would bring God's people where the legalist religion of earthly Israel fails to get. Philo already pointed in that direction.
The term Chrestos, later corrupted to Christos (Messiah), is also found in the aftermaths of classical Hellenic philosophy, especially Platonic.
Jesus the Chrestos is also mediator between imperfect mankind and divine perfection, like Philo's Logos. Also the ideal of philanthropy is of significance.
The revolt of bar Kochba leads to the last step of historisation of Jesus. All connections to Jewish patriotism was sundered. It was in Rome, essentially in refutation of anti-Judaiser Marcion, that this step was performed, leading to the catholic church. Besides being docetist, the original gospel was also asceticist [or better, encratite; self-disciplined, such as in marriage, wine, and eating animals].
The Catholic identification of creator and father of Jesus triggered a major reformulation of the gospel, denying asceticism and docetism, both for dogmatic (anti-Marcionite) and pragmatic (populist) reasons. The shift from Chrestos to Christos was performed in that context, in order to feign classical Judean provenience of Christianity.
Matthew's is the oldest among the canonical gospels, followed by Luke's and Mark's. Lacking thorough textual and literary critics, Bolland does not care for the redaction history of the Paulines, and puts them flatly into early to mid second century, determined by a compromise between Gnosis and orthodoxy.
Bolland exhibited a very charismatic and eccentric personality, harshly critical to various social groups and institutions, thus making lots of decided enemies, but also adorers. One of his major students was van den Bergh van Eysinga, who cared for preserving Bolland's works for the future. Though critical to church tradition, Bolland was also apparently a religious person.
Besides Eysinga, a certain Wolthuis preserved some of Bolland's articles, and various others made minor contributions to keeping Bolland's articles available.