It’s a difficult subject and there’s no right answer, because it depends on how you personally define things like “colony” and “settler”. It’s easier to keep it at a modern conception, but because capitalism has exited for only a sliver of time, these conceptions will often not match against an ancient/classical/medieval conception, and result in general anachronistic madness.

Here’s a couple of historical examples I can think of, note that these are not meant to be me epically owning you with facts and logic, I’m some asshole on the internet, what I think doesn’t matter, what does matter is what answers you come up to these things for yourself, I can’t really tell you what view you should hold, because I don’t think there’s a good case either way.

1. The greek colonies of the ancient and classical era. These settlers would all leave from a mother-city (which they called a megalopolis) and settle some other place along the coast. The entire coast of the Black Sea is dotted with ruins from such settlements, everything from modern Turkey, Georgia (where the myth of the Argonauts was placed), Urkraine and so on. Were these settler colonies?

2. The period of great migrations. The various flavours of goths, bulgarians and hungarians that came across the pontic steppe at various points after the collapse of the western roman empire. Most of them were escorted by a warhost, as this was an exodus of an entire people. Oftentimes the locals were none too happy with their new neighbours and repelled them if they could. Were they settlers? Did ancient Hungary did an Israel/Palestine on the native Pannonians?

3. The Rurikid conquest of Novgorod. A Norse invasion of modern day Novgorod coupled with an open invitation to all Norse people of coming over to this new kingdom of Novgorod, that eventually resulted in the many Russian Principalities, (including the Kievian one). The ruling families and settlers eventually adopted the ways of life, customs and religion of the natives, but on one hand, they had a long time to do so, and the Norse were very fond of taking slaves (the children of thralls were also thralls, thralls were traded for, the works). Were the Rurikids, the people that invaded native russians and then raided them for actual chattel slaves settler colonists?

Now as an aside on the First Crusade, not a lot of settling happened, mostly because serfdom did not allow it. Peasants were tied to their land and barons weren’t about to let people leave willy-nilly without then getting a say, in the end they’re losing a tax base. Christians that did remain in the crusader kingdoms were noting how a generation in, they all took native spouses and their kids speak arabic now. Settling if only limited by political factors did not happen in any notable scale.

Moving on to colonialism, this is a tricky one, because the main draw of modern era colonialism has been the vast extraction of raw materials in order to bring back home, turn into consumer goods and sell them off to the now growing middle class of people. All of this is exacerbated by a capitalist mode of production, aka “market imperatives”:

• competitive production
• profit maximization
• the compulsion to reinvest surpluses
• the relentless need to improve labour-productivity

All of this led to more expansion, ever cheaper slaves, ever more extraction and so on. However, before the enclodure movement in England had started, such a mode would not exist. Commerce was dominated by merchants, whose means of enrichment was very much different, as it was limited by the boating technology of the time: you could not carry a great weight of goods and you could not carry them for very long distances. Moreover there was no budding consumer economy to sell most things to. Peasants were mostly self-sufficient petty producers. Note that I didn’t say “commodity producers” because most of the things they made were for use value, not trade value (and commodities are created specifically for their trade value). This meant that merchants were “limited” to trading luxury goods (which cost a lot per tonnage) for the consuption of local elites which used non-economic means to extract wealth out of the peasantry (political, religious and military). In essence the merchants were doing endless arbitrage between local, isolated unconnected markets, and a lot of their rising profits were not a result of “market imperatives” but of commercial “innovations”:

• monopoly privileges
• superior shipping
• sophisticated commercial practices and instruments (financial institutions and arbitrage)
• elaborate commercial networks
• far-flung trading posts
• military might

Each and every one of these stifled one or more of the aforementioned “market imperatives”. In fact, merchants would resist the initial creation of more connected markets (things such as a national market) as their entire profits were predicated on there being separate markets and them owning monopoly rights to certain routes.

So if there were no settlers, no large scale economic extraction of wealth (there were extra-economic extractions of wealth, but that’s just feudalism for you) in order to enrich the motherland, then in what way were the crusader kingdoms settler-colonialist. In the same regard was something like the Aglabid conquest and ensuing settlement of Sicily also settler colonialist?

edit: i know this is structured like i’m trying to “just asking questions” / whatabout you into saying “no, the crusader states were not colonialism” but you can say “the economics don’t matter, these are all some form of setter and / or colonialism” or “these are their own thing but belay early experiments into colonialism” and i think those are fair positions to have, just that i can’t make that case for you, for what it’s worth i don’t think “this has nothing to do with settler colonialism actually” is the correct takeway from this dumb post i made, just that historically, things are fucky and there’s rarely 1 to 1 comparison to modern things